if you decide to do a small notch and keep the bed height you will need at least 3" above the axle and then you really should install some of those beehive style suspension snubbers over the axle so you have lots of cushion effect there. the ones used on the S10 rear suspension bolt up through the middle so you could use something like that. there is also the timbren system in the link
https://www.etrailer.com/Vehicle-Sus.../TGMRSB4S.html
if you check ogres thread he has a small notch above the axle in the stock frame.