Def go with BHO, I'm a huge fan, I make it using every part of the plant including fan leaves.. Only thing I leave out is the roots. I've already had my share of arguments whether or not males produc any thc, they do. Not as much as a female obviously, but before the pollen sacs open up, there is a fair amount of thc in males.. U say u have 4lbs ground up male? I don't see how u could not get a decent amount of hash oil.. I've never made with a male before, but I have reused female plant twice over with BHO.. n the second time was less than 1/2 as much, but none the less, still there.. Thc is underlying, on the INSIDE of leaves n stems as well as the stronger trichome on stems and amber trichomes on leaves. Go for it 100%, butter is cool but 4 lbS could get messy, lots of butter, get fat lol..
Go for the bho method, but DONT use PVC.. I made a simple thread that's really easy to make an extractor n how to use it, there's one in the f.a.q. Too, but I feel mines extremely simple to follow
good luck n good high lol