No gas reaching the top burners.
Hi all, a bit of background story: just acquired this Magic Chef gas range in new condition as wife is sick and tired of using the electric stove. Time for a replacement.
Not wanting to fork out thousands for a new unit, found this one from someone upgrading, which was running off natural gas. These convert to propane easily, although I suspect I may have caused some damage along the way. Here hoping to get some clarification and how I can get this guy working again.

This being a Magic Chef/Whilrpool, converting to propane was a snap. The instructions manual shows the procedure in detail. What it didn't say is that I needed to run a regulator off my propane bottle. And this is where things get tricky.
After following the conversion procedure to a tee I run a test using a 20lbs propane bottle and a new 6' hose. That didn't go well as too much pressure was being fed into the range, to the point where things got scary. A couple of subsequent tests WITHOUT the flame showed propane whooshing through the top burners, with a loud horn-like sound. That's when I realized I needed a regulator, as the one inside the range (see pic) clearly didn't handle the high pressure.

Today I did just that, purchased a twin chamber regulator, new 3/8" hose and an adaptor. Hooked it all up, turned on the propane and nada. There's no propane reaching the top burners. Nor the oven.

Regulator is a proper 11"/water and it came from a proper propane store, not a big box store. After disconnecting the hose from the range, I could see propane coming out just fine, at a "civilized" pressure. But upon connecting it to the stove, nada. As seen in the pic the point of entry is the built-in regulator. Could the high pressure from my previous test have damaged it? Is there a test I can run to ensure this indeed is what I need before I buy a new one? Or could the issue lie elsewhere? Here hoping for some input. We're eager to get this nice range working.