Speedmaster rockers

I have two sets of rockers to go with my little 383 stroker small block. The set currently on the engine are W2 Norris stainless steel rollers. I also was given a set of MP aluminum W2 rockers with my spare 365 small block engine that I purchased last September. I though about putting the MPs on my 383 but they just look and feel so flimsy compared to the Norris rockers.
One problem that I was having towards the end of last season was issues with some adjusters getting loose on the Norris rockers causing some pushrod issues. Thankfully it never caused any serious problems but only because I got lucky and dodged some bullets. I racked my brain trying to figure out why these adjusters were working their way loose, and it was almost always the #1 and #6 intake rockers. I tried different adjusters and always made sure the lock nut was tight but after a few runs one or both would be loose again. Now I'm thinking it may be due to my pushrods being too short.
So my question is, does anyone have experience using the old Norris stainless rollers and the MP aluminum W2 rockers? The Norris rockers look bullet proof to me, and as I stated earlier the MP aluminum rockers appear flimsy and weak by comparison. Also, could short push rods cause the adjuster problem? I'm out of ideas.