I suggest you chat up Warn and confirm just what their "mechanical brake" consists of. Also confirm what their "line pull" spec really means. Usually, winches are rated for what the winch can pull, but the manufacturers seldom specify the grade, or surface, or whatever that pull is against. This is significantly different from the actual line load at stall, which is always specified as a function of drum wraps for hoists. Personally, I would not use a winch for a dinghy hoist, particularly one your size. I would use a HOIST, which is specifically designed to stop a load once power is removed. Something like this: https://www.warn.com/12v-dc2000-indu...st-winch-63899
Yup, MUCH more expensive. Sigh.
I've tried many, many "winches", both cheap and expensive, from Warn and others, as dinghy hoist motors. NONE had other than a modest drag on the winch line, if power was removed (i.e.-the hoisting operation was stopped to swing out the davit, for instance). Thus, constant blipping of the up-button was required to hold the dinghy in place mid-pull. Winches are designed to pull stuff, not raise and lower things.
Sometimes, you can get away with multiple block and tackle to reduce the line load, and thus get by with a winch. Or, you can oversize the winch, and hope the drum drag is sufficient. But often you run into drum capacity issues, and attendant tangling and general hasselation, and thus a substandard (or worse-unsafe) operation. I wish Rule still made there 2200 winch. It did, indeed, have a line lock, and at a reasonable price. Sigh again.