Charts can be wrong and I can be wrong but I have a horrible feeling all this was in vain and would need redoing all over again for lack of oil lubrication listed at 11oz of PAG 150 with 68oz 134a. I see you have 6.5 oz oil - oops. Not enough if a single system.
Alcohol to flush? IDK - use flush for A/C some will use lacquer thinner and copious compressed air.
Compressors are usually up high with m.y. 1995 area so slugging isn't as likely as a low mounted compressor.
Take pressure with front on only or they will be erratic IMO and observations on similar, Suburbans to be exact.
Temp pressure relationship is only valid with all observations including just ambient and output temps plus at what RPM and fan speed or aren't helpful yet.
Also if this wasn't mostly charged before first start up or compressor spun prior to installation it was probably harmed or destroyed mostly rather quickly and the debris is all back where it would be all over again.
Pressures you listed would condense refrigerant well or much, performance if any lousy and the dragging on the belt is probably the compressor seizing again and hate to say not a surprise.
Bummer. At this point and age of the van do you want to spend all this money and more all over again? Of course up to you.
This is good into also listed up top in knowledge base but the link to it is here. Long read as it's critical ever step of the way or this common total failure is the tuition for doing it incorrectly unfortunately,
>> Good read link >> http://aircondition.com/tech/questions/ ... Procedures