In the family business we have built 757 full size boats from 10' flats, up to 65' crew boats, speed boats and cruisers, I have built approximatly 150 R/C airboats (pullers and pushers) and about 75 of the R/C race boats(mono's, hydros and outrigger hydros). The little guys do have some comparison (just the simple basics/the looks) to full size boats. The only true way that the little guys can be compared to full size, is if you slow the little guy down to about 8mph. Example: trim tabs on a full size(15') may only extend 3" to 6" beyond the transom, which is very little when compared to 1" of trim tab on a 24" boat. the hp to weight/size ratio also has a large margin of difference. Now with this said, comparing a full size to the little guy can give you a small starting point.
Back to the little guys, you can place your engine just about any where you like on your boat as long as it is on or very near the center line of the boat, if the engine angle is matched to the placement location, this does not mean the preformance will be the same.
Starting points of the little guys, would be match the prop to the engine to the boat, then match the placement location of the engine to the boat, then the AOA to the way you want the boat to handle. Next you call up your buddy for a race and blow him out of the water.