Hi Chong, I have just got a wetmount kit for my Canon recently from the Canada, the kit comes witha great custom film/glass mount holder. I can recommend the kit as a whole but maybe the guy would consider a film holder alone if you ask. I would think that maybe mounting to a glass plate would be better for 10x8 as the film would sag quite alot I am guessing! I can send you the details if you are interested, just PM me, the kit is quite cheap considering...
I have scanned the slide I was talking about and have attached it below.

Details; MPP, 90mm Schnieder f8, Fuji Astia. 4sec@f45. no grads or polarizer.
The GG is sooo dark I was struggling to see what I was doing, getting the plane of focus right was a real mission! That and the fact that the camera was about 3in above the ground(I am not gettin' any younger after all)
The guy I was with has an Ebony 45SU, his GG must be 3 stops brighter I reckon':shock:'
I could see through his better WITHOUT a darkcloth than through mine with'

'
It came out a little redder than on my screen at home by the way.
Gari