Don,
The performance of the D27 & WOF 28/30 are very similar. There are some design differences, besides the length. The WOF 28/30 has less lift in the center section and the motor is offset to the right.
The WOF 30 version is intended for modified motors, while the WOF 28 size is for stock motors. I find it much easier to build a WOF boat than a built up frame boat like the D27.
The D27 was orginally intended to be a new kit from Dumas to update the Hotshot 24. When K&B Mfg. changed hands and motors were no longer available, Dumas decided against investing in a new kit. That was a good business decision on their part.
However, I had the plans all drawn up for a frame boat so I sent them into RC Boat Modeler. I think I ended up building something like 14 D27s for myself and others and from about the third hull on, I switched to WOF construction.
Well, that's probably more information than you needed, but the NASCAR race is still a few minutes from getting under way down in Texas.
Jerry D.