Haulage missions are broken in Elite and are not great for many reasons. The constant (and super boring and unchanging) wave of 4 deadly Anacondas spawning to interdict you is just one of the problems. Space Trucking in Elite needs a serious amount of love. I’ve been pleading with Frontier on these forums for a few years to throw space truckers a bone. Let’s see what the new era has I guess.
One example: If Frontier had single missions that could fill the hold of larger ships, like 400-700t missions for example, that would do a lot to reduce these interdictions. Stacking a bunch of 120t - 180t missions really does increase the rate of NPC interdictions a lot. Haulage is actually fun in the early game when you can fill your ships hold with a single mission. Once you get above the Python though doing haulage loses all of its appeal. I never heard any response from Frontier as to why haulage maxes out at 180t. (Wing missions are not a thing for solo space truckers like me). If Frontier even fixed this one problem it would make the game way more enjoyable for me.
Stacking haulage missions in a Type-9 for pilots are are not highly skilled is not advisable given current game mechanics. If you learn to avoid the interdictions I guess you could do it. I deal with the NPC spawning 4 Deadly Anacondas issue by doing these missions in my engineered Imperial Cutter which is basically invincible to NPC’s. I can take out the 4 Deadly Anacondas that always spawn because I have 8 zillion shield HP’s. It’s not fun at all though. Just a chore. I don’t even like the look and feel of the Cutter really, I wish the Type-9 was more practical for this kind of play but it just isn’t.
I too would like larger tonnage missions. But not TOO large, as then I'd have to fly a Cutter, and I don't really care for that ship. With the current limitations on the mission tonnage, I can get two 180t plus one 120t mission stacked in my Corvette. I like to do this because the interdicting ships can carry some rather nice trinkets that I scoop up. I'm always gathering mats...