Boutique caps in oil... reliable?

Check out this variety of caps from Jupiter Condenser.

For a vintage sound paper-in-oil capacitor, you might look at their VitaminQ or Comet caps.  According to Jupiter:

These capacitors utilize the same polymerized impregnation fluid developed by Sprague in the 1940s.  Hermetically Sealed and processed under a deep vacuum for several days.  Hermetic sealing keeps oil from leaking out and provides protection from ingress of moisture to ensure long life.  Glass to metal end seals are soldered into tin-plated brass tubes to form leak-tight joints.  Jupiter Aluminum Foil Vitamin-Q capacitors are built to Mil-Spec standards yet developed and refined for beautiful sound.

I have had their Copper Foil Paper & Wax Capacitors 600V in a preamp for around the past 8 years with no problems.

However, I once owned a BAT VK-51SE that leaked out of one of the Bat-Packs.

• I was planning a DIY high pass but instead recently added a Marchand XM46 XLR Passive Line Level Balanced Crossover between my preamp/buffer and my amplifiers, which rolls off my main speakers at about 45Hz.  I cannot hear any noise or other ill effects from having the Marchand crossover in my system, but it does result in improved bass.

How about foil paper & wax capacitors Ralph?  Have you seen problems with capacitors using wax? 

I believe you use V-caps which are foil and fluoropolymer film so I assume you do not have problems with them.  I also noticed VH Audio makes an oil impregnated metallized polypropylene film capacitor, that they market as,  “one of the most transparent and musical oil capacitors ever made.”