Materials question... well, this are my answer:
For me the raw materials gets solved once for all when I start doing Painite in a regular schedule; I have excess of grade 1 - 2 after each mining trip, so I must always go at a raw trader after and I exchange all for upper grades. I am near of upper storage limit on almost all raw since I do mining at least 2-3 times / week. Question solved.
Now, back to the OP question: manufactured, and especially high grade ones... one must take in account the time involved in acquiring them. Add the fun/ boring factor to the equation.
I did a lot of experiences, using advices from veteran players on Tube, then developing my own strategy, since many of the info posted on Tube is years old and many things changed since, making those advices obsolete and useless at the present time.
My personal and WORKING solution, not just for Pharma isolators but for all high grade manufactured, is simple, but require some effort to get the base - and the base, the solution, is our beloved Vette.
Get a combat build Vette, in Solo, load a grade 6 hangar with an elite NPC pilot, make your weapons reload-free ( I use a pair of efficient / vented Huge Beam, 2 Imperial Hammers ( but ordinary rails serve also) with Long Range / Plasma slugs, and 3 MC with Corrosive, OC. You get the MC reload free from grade 1 raw synthesis very cheap ( iron and sulfur, something you get in excess when mining ), so you have no need to dock to rearm, you are ammo free.
Load a class 7 B ( B has better range than A ! ) of Collector Limpet Contr.
Load 128 Limpets.
Add an engineered with fast scan (2 seconds) Kill Warrant scanner on your utility mounts , and bid the scanner to the beam laser key, so each time you fire the beam you scan the target also, auto mode. (This will double/triple your kill credits at the end); Add a Chaff launcher with extra charges, for "hot moments" AND a Point Def. Turret, since many NPC pirate wings will flood you with missiles, sometimes. Add a shield cell, just in case things go south and you need to run.
Search for CERTAIN ReSh - only some of them will get high grade pirates NPC: I am now in BD+11 2673 system, who has 2 of those spots, where you are not bothered with Sys Authority vessels so you can just shoot at anything who came close. Attention: NO VALUABLE things in your cargo, or you will get killed fast !
Step 1 - get on this system and exchange your fuel scoop for a second fuel tank - bigger the better ( those rails with plasma will eat your standard fuel tank very fast, if you do not pay attention ! )
Step 2 - get on ResH, park your armored whale BETWEEN rocks, so you will screw / ruin the maneuverability of NPC small ships who will crash on rocks when they try to avoid your fire, geting you a good laugh ; find a place near of a NPC who is mining there, if you can ( he will serve as a bait for NPC pirates !)
Step 3 - put your fighter in Aggressive mod, and
Step 4 - Engage the bad NPC pirates : ATTENTION: the wings / solo Pirates AFTER will scan you and you wait, until that sweet moment when they are NEAR (1 km or less !) and they turn away, to search for other target ! - now they offer a big belly, flat and nice, perfect target for rails ! FIRST use rails ( most of them NPC.s are elite, and use tons of Chaff, but I found out when you hit them first with rails no chaff is used, otherwise, if you hit them with lasers, you get instantly chaff !) ;
SELECT your first target with some common sense, function of the wing configuration - if you get 2 medium 1 small, target first the small since the class 4 beams can delete an eagle or a cobra in just seconds. Always try to kill the weaker target first, because is better always to fight less than more opponents.
A decent Vette can take AT ONCE in 2 wings of NPC.s , but do not push your luck - better deal with one wing at the time... if you can.
Step 5 - AFTER you have 3-6 kills floating near you, release the limpets, recharge your bi-wave, check the ammo on MC.s and use synthesis if you need, etc, until the Limpets collect all. Drink a beer on mid time if you like, but DO NOT engage other enemies until your Limpets end the work ! Limpets are very vulnerable at fire, you could lose them all in just 2 seconds if something like just a tinny Eagle fly near you ...
Step 6 - after you run out of limpets AND / OR fuel, go to the nearest dock station, get your credits, refill, remember to RELOAD the FUEL SCOOP ( and the Guardian FSD booster, if you have one) - and go to nearest manufactured trader.
From personal experience, I can say this method is, by far, the best, because:
1 - is challenging, I promise you will never get bored
2 - will get you HUNDREDS of manufactured, and 10-15% of them will be grade 2, 3 and some 5 % grade 4 and 5 - but attention, JUST IN SOME ReSh places - not all ! The sys, I mentioned before it is, for now (things can change next weeks...) just ONE of those systems where High Tech NPC pirates will come.
3 - you can get, in 1 hour, something between 7-11 millions credits ( best use a NPC pilot you "schooled" from novice, so you will never pay him more than 10% when he gets elite level)
And in a final note, scan each habituated sys you pass, in your normal game play, for ReSh , AND try those places for 5 -10 minutes; Look at the kind of materials the kills render. IF you get AT LEAST 2-4 grade 3-4 or higher for each 5-6 kills, then the place is worth to bookmark; If you see they drop only grade 1 and 2, the place is not worth your time.
Other methods I see/read about are boring and not effective, if you look at the time involved and quantities...
ResH are not the only one, same strategy / build work perfect also on CNP.s , so try there also.
