RE: WM Dago Red and Jett 60LX?
It will fly sorta like what Proptop described.
photo of the dago here is a 60L installation - full size pipe. I seem to recall he was flying with a 10x7.
The 10x6 or 10x7 would work well on a 60LX install. Trick would be the muffler installation. You really want to avoid using an extension pieces on the LX configuration.
My P-51 is about the same size as the WM aircraft. I think it might be a bit lighter. SJ-46 power, turbojett ---- has a 12x4 up front to actually slow it down for some scale appearance, and in part to keep the plan from destroying itself (not well made). I actually test flew it with a 9x7 prop. Has that same 3" size spinner.... looked goofy, but it flew.
The turbo-jett and LX are not quite the right combination. Works ok, but the regualar SJ-50 or 60L performs better on the turbo since it is set for a bit lower rpm.