Re: switch for tilt/trim
I don't think it would be hard to do at all. I'm no electrician, however here's what I would do.
Trace the wires back to the connections near the transon (probally at or near the relays) and than add a second wire to each of the connections and run to your new switch. The end result should would.
The other solution is to do same thing, but from the original switch, however you would have to make the connections just before the switches, and that would leave you with spices in a hard to reach area. Also thats gonna take more wire and time.
I know I can't explain it as simple as it is, I'm sure one of the experts will chime in and get you on the right path.