From what I saw in the conversion system briefing, after user click the conversion button, all that left for user to click is a confirmation button and there are nothing left to select.
In this shape it might be hard to implement situations where an aircraft can be converted in more than one way.
For instance for a passenger DC8-60s, it could either be re-engined and remain as a pax plane, or be converted into a cargo aircraft, but without selection in conversion panel it does not seems like something that can be done.
Alternatively for aircraft like DC3 there're different competing re-engine designs too.
And thus I think it would be nice if the aircraft conversion function could allow users to select between which conversion to be applied onto their aircrafts