A manual tuner for the FT-897

I have just fitted my MFJ manual tuner on the side of my FT897D. This is a small travel tuner rated at 150W that tunes almost anything.
I tried it with a short whip and also with a wire thrown over the bushes, using two radials as a counterpoise. I would also like to try it with an outbacker-type antenna.
Apparently the wire-over-the-bushes antenna is good for NVIS communications but I didn't know hw it would fare on 20m.
The result was outstanding. I made a QRP qso on 20m with Slovenian station S56P (operator: Bostjan) and I got a 55 signal report.
Now I would like to make a larger case for the tuner so that I can install different connectors for coax antennas and 3/8-24 whips, and perhaps also a 4:1 balun.
The larger case will also give more stability to the radio.