Is there a web site that lists manufacturers' recommended refrigerant oil viscosities and capacities?

Go to www.aircondition.com On the home page you will find a link called "D's Technical Pages" Click on that and poke around. You will find an area that will give you capacities.

As for weight, click on "Straight to the Board" at the top and post your question. There will be an answer to the type and weight for your particular compressor very shortly.

There are some a/c people who have kept very good statistics and suggest PAG 46 for many compressors. Steve Brotherton is one of them and has massive statistical data to back up his statement. To use PAG in a converted system you MUST thoroughly flush, replace o-rings, replace filter drier and evacuate thoroughly. I appreciate and respect Steves endless data.

What you will find from many others is that they will recommend Ester 100 and that's it.

To do it right, find out the weight like you are doing, flush everything thoroughly and do it right. I don't think that Steve's data lies.

My $0.02,