Maybe a daft answer but why not just buy the Icom A22?
It works, the headset adaptor also works, you can get a very cheap dummy (empty) power pack moulding for it which takes 10xAA alkaline cells(essential for emergency gear because all common rechargeable battery technologies self-discharge much too quick).
I even have a circuit for a headset adaptor for the aircraft powered version of the Bose X, for the A22 radio.
The incentive to go for something else are the smaller and slicker American models, which can be bought in immersible variants, supposedly not CAA approved but who gives a damn, but unless one can sort out a proven headset adaptor they aren't much real use for this purpose.
You also need a remotely mounted (velcro) PTT switch.
I had a radio failure during a pre-PPL solo and bought the A22 the same day. When you get into IFR, a total loss of comms complicates the options way too much.