Building it as scale model? Interesting... but... to have the same tail area, I have used a 70% ratio (square root of 2, divided by 2, equals abour 70%. So twice the square of it gives the same as the source, and mixing 144th/72nd does not fit: 50%, 72nd/48th makes 67% maybe acceptable but I fear there is no 1/48 kit for the B-29...