don't see any problem if both armies are based the same... each 'stand' firing is treated as just that. Interestingly, for the Napoleonic adaption of the rules I had to cater for various collections owned within our group...
some had figures based in sixes some in eights. This also made for variable size battalions between 18(smallest) and 32 (largest). I modified the fire factors so that units firing with 8 figure stands got an extra +1 to reflect the increased numbers of troops.
If you look at unit strengths in most wars, battalions vary enormously.
Waterloo for example: some French battalions foughtr with little over 300 men whilst the largest British battalions(the guards) had 1,000!
You'll be fine with your 24 fig units. Interestingly Charles Grant and I gave ULB V a run out at the weekend with my Great Northern War collection. A massive victory for the Swedes
... yes I was the Russians
The rules worked very well. Swedes took a look of casualties on the way in but when they got in... well, the rest IS