Most of the mag-length 75/77gr pills will probably work about as well as anything. I'm not sure they have that much zoot over the 69gr pills; it gets back to the balance between higher BC/ lower speed vs. lower BC / higher speed.
I have tried handloading Berger and the 70gr bullet worked well but I could never get the 75gr to work even after I cut a slot out of the front panel of the magazine. I too would like to get my hands a DPMS magazine.
Hornady's 75bthp (Amax without the tip) seems the highest BC that'll fit in the mag at .395. I would like to know why DPMS discontinued the VLD mag. Seems a good idea. I suspect some of the polymer mags may have a bit more length due to not needing to overlap metal for spot welds.