Jim
I have over 70,000 miles on my TFS Twisted Wedge Heads with Crane roller rockers with no problems. I originally bought the heads cut for WireLoc gaskets but had too many head gasket problems so had them shaved flat and now use regular Fel Pros with no further problem.
I just rebuilt the heads and did not have to have the guides replaced just re cut the seats, new seals and reshim the springs. Seems to me that the valve train geometry isn't too bad other wise the guides would've been worse. One thing to be aware of is that the heads raise the valve cover lip by 3/8" over stock so if you have anything with tight clearance to the valve covers, such as fuel injection, you should check clearance. I used the FMS Cobra valve covers on mine and with the roller rockers I had to remove the
oil filler splash plate and grind out some of the casting bosses from inside the valve covers to clear the rockers.