New coil springs

[novaX522]

I have a 72 c10 long box. Im going to replace the coil springs. I would like to lower the ride height a little bit, but I don’t want to have a harsh ride. I plan to use the truck to pull an open trailer (around 5,000 lbs) occasionally. I am switching from 275/60-15s to 31/10.50-15s, so the tires are 3” taller and will fill up some of the gap between the tires and fender.
My original thought was to use like a 2” lowering block in the rear and 2 1/2” drop spindle in front with stock springs. But, I have 15x8 rally wheels and I think they won’t work with the drop spindle, and I’ve read they don’t recommend 2” drop blocks in rear with 15” tires. The u bolts can bottom out if you get a flat?
So, I’m wondering if there is a slightly lower spring setup that would work and still allow it to tow safely?
Picture is current ride height with 28” tall tires and stock original springs.