Grub4dos -- thanks!
I tried Grub4dos rather timidly - there are a lot of options, I thought I might get an oopsie! But I'm now using that same newly-changed USB stick successfully, to say thank you.
I haven't worked out how to use parameters with it yet, but I'd better mark this Q as solved. It looks hopeful but I'm a SLOW learner!
I'm sure I'm not the only "slow learner" out there!! When I was working, once or twice I had to make "how-to" docs. I had problems until I got some "feedback" - some inexperienced "guinea-pigs" to read my efforts and tell me what they could or couldn't understand. I wonder if there's anything like that in the LinuxQuestions world?