I too have been warned of using buffer in a load other than one calling for buffer. It does seem odd that it would make any difference at all, but apparently it does. :?
As far as wax goes, it has been used for years to seal poor crimps on reloads, usually to prevent shot spill. No problems ever encountered that I have heard of. I've done it myself...
Just keep the burning candle away from your powder! :grin: