It will work in warm weather, but you need to be diligent about cleaning out the flame channel with a 3mm drill, then a nipple pick or wire through the flash hole. The one I shot back in March of '09 at a range in Montana, we had plenty of breech plugs for.
The best thing would be to have Ron L. open up the flame channel to 5/32" and install a vent liner in your plug.
Cecil also made a run of Blackhorn 209 friendly breech plugs for the 5/8" H&R/NEF that turned out to be the dimensions for the CVA pre-QRBP. These have a 1/8" flame channel and the same internal dimensions as the Omega plug. You might contact him and see if he has any left. I never seen him list those, but they were beautifully machined. This was a few years back, so I don't know if he kept them, but they were a perfect fit.
There was also a temporary mod of opening up the 0.028" flash hole to 0.032" - 0.035". You could also install an o-ring in the bottom of the primer pocket. I'm pretty sure the block is adjustable for headspace lockup on your choice of primer. I would make sure to get a spare plug first.
Just remember, what you can get away with in the warm weather, may come back to bite you during season when the temperature drops. There are no shortcuts.
Lastly, get either Federal 209A or CCI 209M Primers. Use these, no matter which way you go. Keep the flame channel clear, frequently!