Slipmatt,
probably there are some more experienced members over this forum that can give a better advice than me, as I plunged into videoscoping just lately.
You should take into consideration that you will use a different ep when videoscoping than your excellent birding ep .
The ep's that are usualy used are 10x-12x , as to minimise vignetting.
The ep's that I heard of are scopetronix, william optics ,and eagleEye.
Surely there are others and on another thread I am trying to find which gives better results.You will still have some vignetting though.
Than you should deal with balance difficulties.
I found that a sturdy tripod and a good head are very important.
For balancing you'll need very long plate for the tripod head or an aluminium
bracket (will serve also to hold your camcorder in place).
If you will not use a home made video bracket, than choose one of the digiscoping adapters that are available on the market.
As for the camcorder (for videoscoping) I reckon that you should use a 10x zoom camcorder. I would opt for a camcorder which gives the best possibilities for easy and good focus.
An excellent introduction and advice at Dr Chan Kai Soon website
http://members.fortunecity.com/kaisoon/VideoSetup/VideoSetup.html
Sassi