Just picked up a 79 SB, need help choosing lowering options.

[Sidepiper]

First post, Just had this truck shipped from CA to Pa, it's a solid rust free shorty and the only thing I plan to do is door panels and put a 3-5 drop on it with 18" wheels.

I've done some research but and not clear about choosing drop spindles over shorter springs or using a rear axle flip compared to using a shackle kit. Let me know what and why you would recommend.

Thanks for the help!