KC, just to let you know, I've used that minion style burn about half a dozen times now and get good cook times. Just did a 9# shoulder over the weekend in about 6 hours plus an hour rest. That was with foiling at 165IT as well to power through the stall. Full spares take about 3 hours and chicken halves have never taken any longer than an hour an 15 minutes. Aside from doing burgers on the grate once, I've never done beef so can't speculate on that.
Also, I've never found a need to adjust the intake using the minion style burn. Maybe its my location (debatable) but you ought to be able to replicate those results pretty closely.
18.5" OTS, 22.5" OTG, CB Silver(Rip), Vintage Coleman Bullet, Pit Barrel, UDS