I really like the idea of a "very achievable target." My current plan is to finish the artillery and infantry for the British and then do the same 1 kit of each cavalry, artillery and infantry for the French and then bounce back and forth between them. I'll probably be starting off with some skirmish gaming like Songs of Drums & Shakos.
For non-skirmish games I'm going to start off with 4 figure infantry units and 2 figure cavalry units, which means I'll be doing things very much in a DBA style until I bulk things out in the future. I'll have 7 "units" with my 3 kits per side starter approach and then build from there.
I have sort of a "maybe some time in the future" goal of bulking out the units to double or triple the size, but to start, i think 4 individually based miniatures will work fine for the infantry. If I'm not doing grand tactical and the 4 figures represent a battalion you can do line, column and square formations just fine with four single figure "stands." Some time I'll have to get some officers and colour parties done, but not at the individual unit level until I bulk them up as 4 guys with a flag won't look nearly as good as 12.
I think it's more important to get gaming as early as possible rather than continually putting things off until I have properly large units and armies.