G'Day Andy,
Given your exceptional telescope making skills, I reckon the Newtonian option might be the best way to go for the following reasons:
1. Potentially lowest cost
2. Wood tube
- has potential to be quite light
- dimensions/baffling/light shield can be customised to suit your application
- is thermally stable
- Looks great
3. F4.5 Newtonian with coma corrector/flattener when correctly built and set up
- provides bright pleasing visual images
- with practice and correct tools is easy to collimate
A couple of other thoughts:
You could reduce the cost a little by going to a Moonlite focuser and standard TV Paracor compared to the FT with integral PC.
With a focal length of 900mm I suspect most of your observing might be with shorter length eyepieces.
Cheers,