My 87 300e conversion works great, I live in Florida.

Left everything stock, I just opened and flushed everything with mineral spirits, blew it out THOROUGHLY with compressed air, changed the dryer, VACCUMED, Partially charged, PURGED, VACCUMED AGAIN, then final charged.

I was told a long time ago that if you are converting, and you are not changing ALL of the parts on the system, you should use ESTER oil instead of PAG oil on a conversion, because the ESTER mixes better with any residual mineral oil that is left over from the R12 sytem. It also is not supposed to cause the adverse chemical reactions that mixing PAG and mineral oil can. I have followed this advice since R12 became a licensed only product, and I have had excellent success.