How much isopropanol is effective but safe for viny?

Surfactant?? I can answer that. It is a substance that decreases the surface tension of a liquid to promote more efficient drying. Same as some dishwasher detergents that contain one to eliminate/minimize spots on dishes.I worked at Kodak for many years and performed industrial radiography. To process the xray films we used a hand processing method (like a home photographer would in his darkroom) to process the films. The final step in the process (after rinsing) was a dunk into a tank of water that contained a very small amount of a surfactant. The films then went into a dryer
Being it was Kodak we used their own product called Photo Flo. I worked for other companies that also did manual processing of films and some used non Kodak film but they always used Photo Flo for the final rinse. It is a very high purity product and is available from photographic suppliers and even Amazon.
Ericsch mentioned mentioned he used 3 drops of surfactant in his brew. Photo Flo in our application was just one cap full of the product bottle to a five gallon tank. So, whatever volume is mixed up, very little is required. It will eliminate drying spots.

Thanks jrpnde!

Only my opinion. And I may be wrong.

The questions really boil down to what bad stuff is in the grooves and what will be remove it. The most likely foreign materials would be dirt, dust, oils. Maybe some grease. It ends up that Isopropanol is not a very good solvent. A weak solution of distilled water with a dish washing liquid, like Dawn, would seem a good solvent for this kind of material. Maybe only a drop or two in a quart of distilled water.  Thorough rinsing would be necessary. Very thorough. That kind of residue from a cleaning solution like that is probably not something very beneficial to a stylus or cantilever.

But I may be wrong. It might clean but leave a residue very difficult to remove.

@boxer12

I use Triton X-100. Photo Flo is also good.

 https://www.amazon.com/Triton-X-100-Surfactant-500ml-Purity/dp/B009RZZB76/ref=sr_1_1_sspa?ie=UTF8&am...

I think I would limit the definition of a surfactant to a substance that reduces the surface tension of a liquid in which it is diluted, in this case of water.  This allows the water to be "wetter", to penetrate better.  Whether this also results in faster drying may be true, but I am not so sure it's a good thing, if so.  If water plus surfactant (usually a nonionic detergent) dries, then it leaves a residue.  In addition to isopropanol, my RCM concoction also includes a few drops of surfactant per gallon or so, and I usually use Tween20 or Triton X100.  (I think Dawn is fine in this application, too.) But I always rinse with pure distilled water to avoid leaving a residue.  My results have been better since I added the distilled water rinse cycle.