I think a slack head angle would probably account for just the type of handling problem you encountered with your Braxton. If you asked Sam about it, he would most likely have asked why you wanted to do a stupid thing like ride your bike with no hands - that was his style, as Jim Merz and likely countless others can attest to! The problem was your riding style, not his geometry error, so far as he was concerned. I suspect Sam planned for the bike to be easy to control with a load up front, but, it certainly could have been an error, too - every framebuilder has made a clunker or two. My current daily ride was made by a very well known custom builder in '98, and though I'd specifically requested clearance for 25c tires, I can't even get a 23c in there. I kept it, as the bike was 3 months late, but it bugs me now and again, just like your Braxton did...
My Braxton 650A touring bike, which is now in my father's stable, recently refitted with STI, new wheels and new brakes, rides like a magic carpet. The best way I can describe it is that it's like sitting down in a comfy, squishy chair - nice for long days in the saddle. I actually feel like you sit in the bike, rather than perched atop it like my other rides. And it rides much better with a load. My road bike - a very utilitarian, rather plain 531SL - is somehow the best combination of '80s Italian and French racing bikes, if that makes any sense. It makes me feel fast, and strong, but it's supple and not squirrely at all. It's my second favorite bike of all times.
My favorite is the fixed gear "grocery bike" Sam built for himself in the mid '70s and gave me shortly before his death. It has Haden birds mouth lugs and braze-ons galore, including the oh-so-sexy brazed on Zeus 2001 centerpull front brake - it was probably early brazing practice for him. The ride is so-so - tubing is probably a little light for me, and it feels fragile. I seldom ride it, but it's still my favorite.
The fourth bike, the MTB, was one of the last frames completed before Sam's death. It's sentimental, but it hangs in the garage because frankly, it's a pig. Most of the MTBs of that era ('87) were pretty long, and crazily overbuilt - look at pics of the pre-SIS Stumpjumpers - but this bike seemed exeptionally clunky, even compared to common bikes on the showroom floor at the time. It was a few years before chainstays got shorter and tubing got lighter... It's a pretty frame, but it was never fun, even when it was brand new. I mostly rode a cross bike in the hills back then.
Sam did build one bike for Ian Hibell - I think it was the bike he rode across the Sahara, though I'm not certain. A second frame was on order, but Sam passed away before he started it. We did build several pairs of wheels for Ian - Super Champion Model 58s on Phil hubs, 40 front 48 rear. I distintly remember the day in '87 when a box arrived in the mail from Ian - it was a pair of wheels, still mostly true, with the sidewalls of the rims worn completely through in a handful of spots. Talk about bizarre. Ian sent them back because he assumed we'd replace the rims for free, since they wore out unevenly! Sam blew a gasket, swore for a week and told me to put a bill in the box with the rebuilt wheels. I've no idea if it was ever paid or not...