Didn’t checked everything but if you follow the guidelines for war period and zone of conflict provided in the rulebooks, Numbers should have been given to the Yaks.
Random can leads to highly unbalanced games but you have to keep in mind that BRS has been thought to provide the reality of those aerial fights. Enemies didn’t called each others prior to engage to each others to agree on a balance force ^^. Don’t forget that the main point in air combat is not to kill every single enemy plane but to force the enemy to break combat before you have to. So sometime being outnumbered ends in a victory anyway.
I think that you should follow those guidelines for the first play as you’ll learn how those card impact a force and its counterpart then go to more self created forces as you’ll know what are strength and weakness of your planes.
About which planes and level, the card state that you must match the most prevalent for both planes type and pilots level. If you got equal numbers I would say go for lower points each time as ,in my opinion, the Numbers card makes sense for weaker forces. I would even argue that usually numbered forces (not only in air fight) is a way to compensate weaker trainer soldiers but people with better historical knowledge may prove me wrong.
Also, from what I’ve understood of several Andy’s interview, the game is not aimed for competitive play at its core but more prone to be home ruled so everyone can enjoy it.
