I know a lot of owners don't rate the FWH front brake but I've not found mine too bad 'considering' and I live in a very hilly area and most of the time I’m two up. Maybe down to the linings I’ve got or brake drum geometry, etc. I’m thinking that if I need to improve the braking, with sidecar attached, I would first try some new high quality linings.
The chair I'm getting is a single seater and only weighs 85 kg (see photo). It doesn't have a brake fitted at the moment but Watsonian do a kit to fit, so it’s an option.
I had a sidecar on an A10 G/F some years ago, got on fine with it and really enjoyed it. Didn't change a thing on my A10, apart from screwing down the steering damper, I kept the solo gearing and standard fork springs. It was a Canterbury double adult, so a big chair and I kept it for just over a year before going solo again when I needed to travel long distances at weekends (sold it to a motorcycle shop for £10.00).
Your right Julian, I bought those a couple of years ago but I didn’t have any confidence that they would be any better than what I already had, so they were put to one side.