72 C20 lowering a tow rig

[Mystery_man]

Ok yall all the searching that I have done for lowering this truck does not tell me if it affects the towing capacity.

I want to lower my truck as much as I can without taking away from the towing capacity. Do bags or drop spindles/shakles? I am looking at towing a 36ft gooseneck to take 2 race cars and tools/parts.

Suggestions? I am new to these trucks and have never modified the suspension of a towing truck. I can weld and do most of my work myself or with the assistance of a machine shop.