I always reccomend GC's with gas operated actions, to minimize or prevent any lead buildup in the mechanism.
If you are going to another mold maker, Dan at Mountain molds, the design will be up to him and what he'll make for you. If you intend to order from LBT, my reccomendation is given above, or if you still want to try plainbase, I'll design the lubrication to minimize leading. I would definately reccomend one of the LBT lubricants, especially if you want to try plain base. Most other lubes I've tried smear a film of lead which is rough on gas systems at far lower velocities/pressures than with LBT lubes.