If anyone was curious, I actually ended up using White Lightning Megalsatic on that last job, it's still a siliconized acrylic so it's hard not to wonder if it's at the same level as something urethanized like Shermax but it claims it will stretch 700% which is pretty good, especially for interior. All the other stuff I looked had other complications, Big Stretch, I think, was a 7 day dry time before painting with oil, I don't like DAP and even the Dynaflex was a long dry time, Tower Sealants recommended their quick dry (can't remember the name) instead of the Tower Tech 2 with the harder enamels like ProClassic Alkyd and Satin Impervo. White Lightning and my Sherwin Rep both said the Megalastic was a good option and I've been very happy with everything else I've used from White Lightning so I went for it. It gunned, tooled and cleaned up pretty nice with just water and the Proclassic Alkyd seemed to take just fine over it with 4 hours drytime. The real test, of course, is time but I'm feeling pretty optimistic.