Right now for the 150 shot I'm running a 38 fuel and a 67 Nitrous and according to the chart I use it's the same jets for 6 or 8 cylinder on that big of a shot. The smaller shots differ for 6/8 cyl. here is a link for the chart I use
http://www.zex.com/catalog/ZEX101-05/PG22.pdf
Looks like when I decide to go to 200 I'll have to start educated guessing also lol.
I have some jets if you need some. Let me know the size you wanna try out and I'll see if I have them...no charge.