There were some pretty extensive threads on this topic on Delphi, but alas, they aren't here
Yes, many of us use a witches brew of gasoline and toulene. I hate to ask say it, but your best bet is to take a trip over to the old board and do a search. People posted ratios and other tips in the thread over there and I guess the threads still exist for a reason.
You might want to distill the threads down into a summary and post it back here so that knowledge is not lost with the Delphi board.