As you may know, in the 1.37 patch to get to 5's you need 4 rank 4 planes researched and bought. If i go line Yak+Mig, which I want to do at rank 4 I will be forced to grind a new line of planes(i.e. Lagg) just because at rank 4 there are not enough mig and yak planes to research(only 3).
I do not want to go Lagg and Yak line but it seems that would be the only viable solution to have enough planes to move to next rank and still only use 2 tech lines.

What are your thoughts on this?