Designing Great Beers has a section on recipe formulation that discusses the use of Gravity point in detail. I use this for Partigyle mash development a lot. I generally get 3 beers from a partigyle mash with this method. A big beer in the 1.080 area, a standard beer in the 1.050-1.060 range and a small ale in the 1.030-1.040 range. With the addition of some specialty/steeping grains (Crystal, roast, etc.) you can really change the character of the subsequent beers. I like to run the first infusion/mash with just base grain, I use Golden Promise for a strong ale/barley wine. The second infusion would be with and addition of some toasted malt(Victory/biscuit) and some crystal. The third infusion would include some black malt and chocolate malt. This would give the following - Barleywine, Pale ale, Brown Porter. 3 beer, one mash tun, one brew day. A bit longer than the normal brew day but I can triple the output with the addition of a few hours. And yes I have access enough equipment to do this.