Sorry cobs, you managed that as soon as you decided to post on here

If I were you, I'd fit a brake, but I'm an old phart who'd like to become an older phart.
35mm tyres? Why? Yup, I'd change them, but only after I'd ripped the stuffing out of them perfecting my skidding. On the other hand, with cheap hubs, you can strip the locking ring thread by moving the cog backwards and popping the lock ring over its thread - I've done this to two Quando hubs which says as much about my technique (wasn't moving my weight forward) as it does about hubs made of cheese.

Your wheels were built on a machine which builds things within set tolerances. It's not unusual for even expensive machine built wheels to go out of true. Retension and retrue them and you will probably find they'll do quite well.

I reckon you've made a good buy, and it gives you something to ride while you plan and excecute your next build ... because there will be another one.