If it helps, I found 33 Antimony quite quickly (half a tank of SRV fuel) in Metallic Meteorites, and the odd Mesosiderite on planet Strauss, in the Fomalhaut system not so long ago (Now the Beta 1 materials shuffle was fixed in Beta 2) and the rest of the planets in that system usually have pretty impressive yields as well. Have you found any Rhenium yet? The pristine Metallic rings of Delkar 7 didn't seem to drop any at all in Beta 1 and I haven't been back there since because you mentioned Boron was also missing and the drop rate on Lead was very low in an earlier post (I think it was you?).
I was also looking for HGE USS in Nanomam earlier and it seemed the spawn rate had improved considerably?
Regarding the variable upgrade RNG, may I suggest for logistical supply planning that the RNG factor may as well be removed completely since the result will always be the same so, for a brand new engineer (or pinned recipe at any other station) it always takes exactly 3,3,3 and 3 rolls to achieve G1-4 like it used to, and maybe 6 rolls to fully max G5.
For a pre-maxed engineer that is already at G5, may I suggest the perfectly logical and organic "Golden Mean" or "Fibonacci" sequence of 1,1,2,3,5 for G1 through G5 respectively (8 rolls to max G6 if its ever introduced). This would remove another point of frustration - Thinking you have enough mats to complete a job, but then you don't, and have to go find more.
Regardless of whether you harvest or swap them it's still annoying if you expected to finish something before bed time...
[Edit: Work tomorrow, it's 1am now I should be able to finish off this job and still wake up on time... WHAT! I'm out of mats again!? OMG! *Throws mouse at monitor and logs off in disgust* Has a bad sleep and shows up for work really grumpy... "Shut it Spaceloach, who asked you!"]