There are lots of model airplanes that balance further aft than 37%. It's quite common in the free flight world where the tails are large and a long way from the wing. Even in the current model sailplane world it's not uncommon to see folks balancing at between 35 to 40%. It's all about the aircraft neutral point rather than any fixed airfoil based constant.

Now that flying wing with the CG at 35% would have been a merry handful for sure......