Looking at the level 40-50 progression, it's a hard set of levels.
I used the BLM solo guide on my SCH, and found that going 40-45 at the Temple of Uggalepih required me to sit at a zone line at the first map (F-6 I think), something a SMN will not be able to do -if- he needs to recast.
Also, the camp at Cape Terrigan from 44-49 is awesome from a nuker's point of view, but again, stuff up there will eat your face. The best camp is the one on the ledge north of the Outpost at G-8. There are three gobs that roam around each other, and watching their pathing, you can find spots to stand and kill. However, I remember time being an important factor, and I went through a LOT of Ninjutsu tools for Invisible.
Pso'Xja sucks, Castle Z. sucks, Beaucidine Glaciar sucks in that range, avoid those camps if you can.
Last, accept the fact that you're going to die... a LOT. When my SMN was 52, I went to Ifrit's Cauldron for the first time and died 7 times from 52-53. Bomb-solo'ing is actually easier because there are fewer camps, the mobs always behave the same, and you get used to the practice.
BST pet camps vary a lot more, and shit happens. Just don't get upset if you start your day by losing a thousand experience points.