Meseems you're fixated on having the C/G at 25% MAC. Actually, the location of the C/G is heavily dependent on the airplane's configuration and even the wing's airfoil.
The C/G calculators usually calculate the location of the Neutral Point (NP, in % of MAC) and then you choose a C/G location ahead of the NP. The difference (also measured in % of MAC) is also called the static stability margin. The calculator may even let you choose a stability margin and then calculate the C/G location.
For the Yak I'd assume only 2% to 5% MAC but for your blue bird even 5% to 15% as you see fit, that is depending how much decalage there is and how much stability you like.
Probably you'll come up with about 30% MAC for the Yak and 40% for the blue bird.
FWIW.