The only thing they are doing to my master cylinder is installing a brass sleeve as it was pitted where the water sat in the bottom. I'll do the rest myself and made that clear to them in fact. I won't be using silicone as it's not neccessary. While I agree that it is a better fluid in the sense that it is non-hygroscopic, thus eliminating future rust, the only other advantage is the higher boilling point. That is what the DOT 5 rating relates to. DOT 4 and DOT 3 have lower boiling points. This is important in applications that are generating lots of heat (race cars) but not in a 1969 camaro. The problem with using DOT 5 is that you must remove all traces of DOT4 and lower from the system including residual amounts on the seals etc. Unless the system is completely dismantled, flushed and dried there will likely be a problem with the creation of sludge like material as a component of dis-similar materials. Doing a complete frame off restoration and starting new it's the best way to go. It will be good 100 years from now. Anything less than that type of resto and the potential problems out weigh the advantages. There is absolutely no conflict with brass and silicone. That is a myth. (not unlike the thousands of other myths in the automotive world)
Jerry, thanks for the reply to my inital email. Glad to hear you guys are busy. I'm not surprised that you are by what I read on the site.