THe way I do it on my 17 is this :

1, Finish Tack (or gybe)
2, Place tiller under my aft armpit and hold it
3, Pass mainsheet to (now) free aft hand
4, Grab trap and hook on
5, Go out on the wire by firstly getting your bum over the side and push / launch yourself out to fully extended and at the same time grab mainsheet from aft hand and release grip on tiller (from arm pit) and catch with (now free) aft hand.

Part 5 will become one fluid movement (with practice) and you do should be able to do it without changing the mainsheet tension or the rudders moving at all - If you don't catch the tiller first time (and it is not too lumpy) you can catch it on the re-bound from the deck.