Need Rear Suspension Set-Up Help - '68 Cam

[CamaroNut]

My son and I just started re-building a '68 Camaro together. Not real experienced, but quick learners. A mechanic friend is selling us a 350 stroked/bored to a 383, re-built TH350 and shortened (50" backplate to backplate), 4.11, 12-bolt rear end (Eaton posi) that we want to swap into the car. It's set up in a '76 Pontiac Astre (Chevy Vega) body now. I'll have to have a shop weld on the proper brackets for mounting the leaf springs. We have the original mono springs and a set of 5-leaf.
Question is - given the increased horsepower, can we go with the mono, or would you recommend the 5-leaf? or maybe a 4-leaf? Don't have the $$ for an IRS or anything fancy - this is a just a driver. Thanks.