MJD...I couldn't get the RX to fit, so after finding out that there is no "end connector" version for the DX6 radio, I tore out the floor and grafted extra material onto the center ribs, then replaced the floor. The covering will have a tougher time conforming to the assymetry underneath, but it's at least hidden undeneath where I won't have to look at it.
The later model Spektrum radios do have end style RXs and they would easily fit, being only something like 3/8" tall.

PS, thanks for your vote of confidence with the fin. This model is built largely out of that punky wood that is as resilient as a graham cracker so the first test hop will be with reduced power.
I got a couple 200 mah LIFEs and a LIFE charger from Tower. The charger output is wired backwards, so I'll either return it or just tell them to send me another one that they've tested.
I used the 200 LIFE already with the TWERP and that really put the vertical performance over the top. It shaved over an ounce off the original weight with a AAA cell pack.