96-99 BLMs

I would use a TT chip with those 42.5 lb. injectors, if it doesn't already have one in there. 47-50 lbs. at idle is too high, turn it down to around 43 lbs. and recheck your scanmaster #'s.
They're trying to tell that the reason your BLM's are so low is because your fuel pressure is set WAY WAY to high.

42-43# static (vacuum line off) is the best setting. If that yields lean conditions at boost then you have other issues!! LIke maybe a defective fuel pump. To check this does your fuel pressure go up one pound for each pound of boost?.

Knowing what chip you have would be a big step forward also.