I thought the FOOT was the best "boost cotrol valve". Set the LDA 'till you "break" (just starting to) smoke, both on "tip-in" and on full boost. Keep it simple. Too much smoke, you're just wasting fuel and cooking your turbine. No smoke, ok, if your a "greenie" :roll: or bring in some more fuel.
Once you get it where it works best, forget about it. Up to it's limits, it'll give you the same results and keep up with any changes to make with air flow.
Like Ron Popeil says "Set it and forget it!"
Alain