172 N to 172 S transition

My flying club is going to trade our 172 N (only airplane) in next spring
for a 2 -3 year old 172 S or SP. We'll be moving up from a very simple
VOR - Loran panel to GPS and possibly autopilot. I can't imagine that we
can just put a new plane like that, with fuel injection, boost pump, etc.
out on the line and let people start flying it without a checkout and an
hour or two of dual before turning people loose in it. With 25 members and
one CFI who tends to be busy in the spring, that could take a while.

I'm thinking that we should plan on operating both planes for a month or two
so that people can keep flying until they get checked out. It will be
Spring, the weather will be improving and everyone is going to want to fly.

What do people here think?

--
Roger Long