Wow, lots of great carb information here, I think I have digested most of it.
With regards to the "pilot screw" I will call it that from now on since that is what its called in the service manual. The consensus seems to be to start with 2-turns out and than adjust from there once the bike is warmed up.
As for the carb mods:
If you look back at my previous pictures you can see that the slide is already drilled with one hole on either side of the needle. I believe this is how the carb came stock, but for reference the top of the slide looks like this:
If anyone thinks otherwise than please let me know.
As far as I can tell it does not look like the needle was ever shimmed with washers and the spring does not appear to be trimmed. Judging from the responses I should leave it this way.
Likewise, the best way to improve performance and throttle response would be to get a jet kit or spring for the TM33 carb, instead of fiddling with shims, and trimming of the spring.
Thanks again for the explanations of the BST carb mods. I think I am finally beginning to understand how all the components work together.