Hi Tom
I may yet send the bevel up smoother back and get the veritas custom 4. It’s mouth adjuster takes one complication out of the equation - hate the idea of moving the frog forward to adjust the mouth.
Moving the frog in a plane with a cap iron essentially never happens. You have to leave enough room in the mouth for the cap iron not to stick the shaving against the front of the mouth, and at the point it's set there, unless you start changing the iron thickness all the time, it will work for any shaving you could physically get out of a plane.
The draw of using a tight mouth on a plane is that it's simple. The problem is that it's limiting and it really doesn't provide a clean surface if it's functional, and still only in tiny thing shavings. It's a choke to prevent you from being able to take thicker shavings, and for that purpose, it works, but it punishes you with resistance and still lack of complete tearout protection. A steep planing angle or a cap iron will eliminate tearout. of those two, the easy one is limiting, the one that takes a couple of weeks to get the hang of isn't so much.
Moving the mouth creates a bigger problem - it creates the need for precise machining and clean surfaces inside the moving mouth, no rust, no dust, etc. if it's never moved, it's probably never a problem, but it's unnecessary.