Well now, there's a question we don't see here very often! I am absolutely NOT any form of expert about this car or its engine, but I do recall reading an article maybe 6-8 years ago where an owner used Mobil-1 15w-50 in one.
What condition is the engine in (besides the compression issue)? What oils have been used to date, or at least recently? Just a thought, but if the thing has been fed old fashioned non-detergent oils for some time, it would probably be smart to stay with one of those, and change very often.