After putting this on the back burner for 6 months, I'm back at it, and ready to report initial testing is showing 5000cst to be the oil of choice! Hopefully, I'll wrap up the whole thing in time to take it to my daughter on Sunday. It will be mated with a vintage Pioneer SX-850 receiver and some JBL speakers, which she's been enjoying for a while. Thanks everyone for the help and encouragement!