Thanks for all your replies and the ensuing discussion; it was very valuable reading for me. I am still leaning to do an R12 recharge on my 1992 300E. Since R12 is unavailable legally anywhere in Canada, kindly refer back to my original question regarding suggestions of honest techs in the US that will do R12 and won't charge me the dreaded $100/lb. I also want to avoid the instance on another thread where the tech said he was putting in R12 and quoted less than $50/lb but ended up putting Freeze 12 instead. The cities I can easily get to are:
Buffalo, NY
Pt.Huron / Flint / Saginaw, MI
Toledo, OH
South Bend, IN
Boston, MA
Dallas / Ft.Worth, TX

As Larry Bible said, (paraphrase) do the job properly with the proper ingredients. I fully agree!!

Thanks again for an informative discussion,
ARVY

__________________
ARVY

1999 E430
1999 C230 Kompressor
1992 300E (write-off)
1984 190D 2.2 (sold)