MRL Roller Lifter Street Durability

OK, here's a little comparison. I've been rebuilding Harley Davidson engines since the '70s. Currently I work for the largest manufacturer of aftermarket H.D. engines in the world. You might have seen some of our engines winning in the NHRA P/S bike class.
Anyway the H.D. valve train is "the most" horrible thing you've ever seen! And it takes lots of spring pressure to keep it stable. If you ever saw the spintron footage of one of these things you wouldn't even want to stand next to one when it runs.
Right now in the production street engines that are being sold it has a 640" lift camshaft and a set of triple valve springs. The installed height is 1.800 with a seat pressure of 170lbs and the open pressure is 450lbs. This is very similar to what you're running.
But my main point here is that these engines run a roller tappet. They have since the '20s and the axle on these tappets is so spindly it's incredible. I believe it's around 7/32's in diameter. But the amazing thing is that these things very rarely fail. Plus I know where theses parts are made and I will go out on a limb here and say that I'm sure that the ones that you're going to run are made to much higher standards.
The bottom line is that I would not worry too much about it. Get out and drive it!!!!!

My 2 cents................Ted