Which leafs for 87 R10?

[D13]

1987 R10, 6.2 diesel LWB, every option (PW, PL, A/C, auto, dual tanks, etc). DD commuter, 70 miles a day. Rarely put any load in it. Factory rear spring pack is 4+1. Need to replace the rear axle (at 215K), figured while I was in there I would do mild drop, either reposition hangers or swap the axle on top of the springs. Eventually will do a 2 1/2" front drop, but not quite yet (parts to drop and rebuild are almost $900!). Thinking I might freshen spring pack and add a rear bar. With the 6.2 it'll never be fast, and it's really nose heavy, but I'm not fond of slow esses on the country roads.

So my question is the rear spring pack. Should i get another 4+1 or go to the 3+1?