It would be easier to make some tuning plates than to fiddle with the Yoder heat management plate, in my opinion. These heat management plates, with their rows of holes, aren't really adjustable within the area of the plate itself. You can move the plate back and forth, but in the case of the Yoder heat management plate it's so long there isn't much room to slide it, and it has very few holes in it near the firebox end. The angled sides also present an issue if you want to make the plate horizontal.
With tuning plates (which is what Lone Star Grillz endorses) you can create large or narrow gaps between the plates, eliminate the gaps altogether, or remove them if desired. The biggest drawback with tuning plates is the initial investment in time needed to experiment with placement in order to determine which configurations would work best for your various cooking strategies. Lone Star Grillz includes the tuning plates as standard equipment, and they also employ locking screws in all their trailer models so the plates don't move during transport.
This unit has rails for the tuning plates, but you don't need rails if you cut all the plates to fit precisely between the sides of the cooker.
Actually, the reason Yoder's heat management plate has such a tall lip is because they mount the firebox way too high on the cooker (as noted many times before). Joe Phillips himself admitted the firebox is 1" above the center line of the cooking chamber, which to this day I still can't understand. I suggested they did that as a trade-off to make it easier to cook over the firebox, i.e. less bending over, but that is a devastating trade-off for a feature that isn't even the main use case for a smoker.
Looking at photos, it is clear you would still need to extend the "ash seal" as low as the heat management plate in order to use tuning plates because the bottom of the ash seal is at the same height as the lower cooking grate. You don't want your plate(s) too close to the cooking grate because they generate so much radiant heat they could burn your food. There's no great solution here without lowering the firebox (again, my opinion).