Re: Rough cost to convert tiller to wheel
I much prefer having a tiller and would certainly not bother converting a T34C from a tiller to a wheel. There are plenty of them out there that already have a wheel and you will have plenty of other projects to deal with, so why create one?
For what it is worth, I have an S&S designed 34 footer from the same era. A wheel would take up a lot of space in the cockpit permanently. With the tiller, it takes up space while sailing but folds out of the way nicely when at anchor. I haven't sailed a T34C, but suspect that like most S&S designed boats they are well balanced, so the use of a tiller would not be an issue.
While I can see how one might feel differently about this for an offshore passage, if that is your plan on a regular basis I would expect that a wind vane and/or autopilot would be in use for much of the time. Incidentally, the same goes for a wheel too. Hand steering for days at a time would be tiring either way.