I agree with Kush, we are fishing for large trout. A spring/pawl reel is all the drag that is needed, but using a quality drag at higher settings is not a detriment either.
As for designing a reel with a spring/pawl check, there are too many limitations in the design. From an engineering standpoint, it is a doomed design from the start- metal fatigue will get the better of it and there is no way around this. If you have any old perfects kicking around, look at the ratchet gear and see how the the teeth have rounded to the outgoing direction creating less resistance because the pawl does not move as far to energize the spring. 5 thousands does mean a lot.
For my .02, I base my drag on the hook I am using. If I am using a heavy wired iron (Alec Jackson 1.5's and the like) that will not straighten out under HEAVY pressure, a strong setting (1 to 1.5#'s at the backing knot) is probably a better idea to help bury the iron.
Things get tricky when using the light wire hooks. A heavy drag will bend them and help in long/short line releases. For these hooks I set my drag at "click pawl" and lightly palm the extra. The needle sharp hooks will find a hold and will be less likely to bend. If you have a spirited steelhead that is dragging around all of your XLT plus 20 or 30 yards of backing, I am not sure that there is anything you will be able to do.
Five pounds of drag at the backing knot (not the arbor knot, but the backing/flyline connection) is a lot of drag. A Bogdan 150 with 125 yards of 20# dacron with the lever put to full drag is just under 3#'s. I set all of my reels to about 1.5x's "click pawl" tension (approx. 8 to 10 ounces) at the backing knot unless I am fishing a strong hook. There is no need to purchase a scale for setting drag tension. Just use Fred's plastic grocery sacks and fill them with your favorite cans of beer to get 12 ounce increments.
One last thought, horse-collaring a fresh 32" hen fish with 12# tippet and a strong hook with 2#'s of drag is quite a violent affair. It's a kick in the pants and sometimes gets the fish to go even more crazy.