Jim
They will work fine in your curved 20 round D&H magazine.
I use Magpul 2nd generation anti-tilts in all my duty ready 20 round and 30 rounds magazines. They all have been 100% reliable.
My magazines were also 100% reliable with standard USGI green follower, but the Magpul followers give me a little extra peace of mind.
They will
not work in straight 20 round magazines such as NHMTG.
John