If that's the case then may I suggest
The War Games Foundry
They are a bit prices but by far the best in 25mm scale
Old Glory is an alrite range if your after the 15mm market
Hope that helps
Wouldn't know actually ... as I don't play those two games. ..
Only have my hands on Ancients Wargaming ... all the GW stuff ... Warmachine ... and now am into Flames of War ...
Joans ... it broken down into 3 eras ..
Early War 1939 - 1941
Mid War 1942 - 1943
Late War 1944 - 1945
Ok ... first off I have to say I'm a Moderator on the Flames of War Forum ... (which is an unpaid position) .... so I'm not here to push the game ... I play plenty of other game systems as well .... Now that's clear up ...
Yes the game uses 15mm models
I've got the rules and the rules set...
My friend the internet and book stores are a great fountain of knowledge for finding the proper feel to how an army should look like ..... you can find other people's painted armies on many internet sights ... and books can show you the historical colors of an army ...
If you truly seek...
Currently I'm making modular boards out of 10mm polystrene ... so I just cut my streams and rivers into that ... looks more natural ...
This web site will help you alot in building rivers
http://www.terragenesis.co.uk/rivers/riverFP.html
and other stuff ...