Hi Peter,
The TMB has a FOV of 60*. I've not tried an LV10mm. Give it a go however. If your C8 has a drive in it like mine, this won't be a problem. I'm not a fanatic when it comes to alignment of my EQ mount as I don't do imaging, but on occasions, I manage to fluke a good alignment that sees a planet stay in the FOV for over three hours and not need to touch the Dec or RA controls.
Either a 10mm or 9mm will give you 200X (give or take with the 9). This is well within the theoretical limits of the C8's aperture diameter. The max. magnification for a given diameter is 50X per inch of aperture. So, for the C8 that's 400X. The limiting factor is actually the atmosphere, which rarely allows even 200X to be used regularly. Anything higher magnification wise is a very rare bird.
As an example, my big dob is 17.5", and has the exact same focal length as my C8. I just don't use the 6mm in the big dob. Not that it doesn't work, but the occasions that the atmosphere good enough to use it, I can count on one hand the number of times in 2 years. 333X is not really an option for me. The same goes for the C8. I would need to be up higher in elevation to be able to use it more often.
Actually, you're out Mudgee way, you may be able to get more use out of a 6mm than me in your C8. You'd be around the 1000m mark in elevation. Something to consider then. Would make for some kick-arse Lunar sketching! (well, that's my thing anyways).
What I do like about the C8 over my big dob, is that its slower focal ratio make it a better planetary scope! The image in the big dob of the planets is just too bright without using filters.
One scope my 6mm TMB excells in is my C5. And guess what? This scope/EP combo also gives me 200X,
!
