I have no idea how could I compare that modified K&B .40 to Saito. 56 (except that Saito will be much heavier) but scale factor 0,8 seems too small. The plane would have wing span 48" and wing area 412 sq. inch.

I guess that reduction to 89 % of original size would be better: wing span: 1357 mm (53,4") and wing area: 33 dm3 (511,5 sq. inch).

Marian