Hi Scabber, thank you for the comments! Interesting questions - so, first impressions of the rephased engine are it's smooth. From tick over and up the RPM range it's very noticeable over the stock engine. Power output isn't noticeably different, albeit, you can tell there's a set of 750 bores underneath.
The weight, or lack of it is noticeable too. That combined with the low centre of gravity, gives the impression of a very light bike. Albeit it's quite long it does turn in reasonably well and isn't too uncomfortable.
Next steps - shake down rides, carb set up, rear light fitted, cam chain tension check, tappers etc etc. On thing I may need to look at is where the chain passes under the lower frame rail crossover tube. I've fitted a nylon guard in any case as I knew there was a risk of contact. However, I may look into a small tensioner.