Don, your planned Roman and Egyptian armies sound HUGE!
I know what you mean about space, Martin and all. Although I'm lucky enough to have a dedicated Playmobil room, being a spare bedroom, it's not huge. I can only fit three 6'x3' folding tables together in it while still having room to walk around them all. Although this is a decent amount of space, I'd really like to double it, as my Roman fortress with nothing else takes up all the space! I haven't yet set up my armies here, but I'm hoping it's enough space in which to have my Romans face off against my Egyptians. If I could do it over again, I would reduce the number of "centuries" in my Roman army, but now that I have them all, I can't bear to part with any. I didn't go quite so wild with my Egyptian army, but I still wanted a respectable force with which to face my Romans.
My Roman Army consists of one legionary "cohort", one Praetorian "cohort", and one mixed auxiliary "cohort":
6 legionary "centuries" each consisting of 20 soldiers, 1 centurion, 1 signifier, and 1 cornicen
1 legionary artillery "century" (to man 6 scorpions and 1 onager) consisting of 20 soldiers and 1 centurion
6 Praetorian "centuries" each consisting of 20 soldiers, 1 centurion, 1 signifier, and 1 cornicen
1 Praetorian artillery "century" (to man 6 scorpions and 1 onager) consisting of 20 soldiers and 1 centurion
2 Praetorian cavalry "turmae" each consisting of 10 soldiers and 1 decurion
2 auxiliary infantry "centuries" consisting of 20 soldiers, 1 centurion, 1 signifier, and 1 cornicen
2 auxiliary archer "centuries" consisting of 20 soldiers, 1 centurion, 1 signifier, and 1 cornicen
2 auxiliary cavalry "turmae" each consisting of 10 soldiers and 1 decurion
1 marine "century" consisting of 20 soldiers and 1 centurion
miscellaneous staff officers and cohort vexillifers and cornicens
My Egyptian Army consists of:
1 heavy infantry "company" consisting of 40 soldiers, 1 officer, 1 standard bearer, and 1 trumpeter
1 light infantry "company" consisting of 40 soldiers, 1 officer, 1 standard bearer, and 1 trumpeter
1 archer "company" consisting of 40 soldiers, 1 officer, 1 standard bearer, and 1 trumpeter
2 heavy cavalry "companies" consisting of 20 soldiers, 1 officer, 1 standard bearer, and 1 trumpeter
1 bodyguard "company" consisting of 20 soldiers
3 chariots for the Egyptian royal family (I may turn this into a chariot "company" consisting of 5 chariots, but I doubt it)
miscellaneous standard bearers and trumpeters
As one can see, the Romans outnumber the Egyptians two to one, but the Romans don't have to all fight at once and I have 220+ North African and Arabian troops of various types that can serve as Egyptian allies to even it out.