I put hydraulic brakes on my 1933 coupe back in the early sixties, when I had rodder inspirations and hadn't heard of the VCCA. The conversion was fairly simple with the bare frame exposed. I have regretted the swap ever since. If you let your car sit for extended periods of time like I do, be prepared for a lot of maintenance and the occasional failure. On a recent pre-36 tour with mostly 4 cyl cars, I was the only car with juice brakes and also the only car that had to be trailered back to the motel because of them. If only I had saved the hardware to return to the mechanicals, I would be tempted to do so. With that said, my recommendation would be to maintain your original set up. My 1931 cabriolet will have mechanical brakes for sure.
Roger