Film holder question from a beginner

Hello LFPF, I have recently entered the world of large format photography with a rather mint Calumet CC-400. New to 4x5, and not looking to drop $700 on a fancy 4x5 epson flatbed just yet, I picked up a used Canon CanoScan 9950F flatbed scanner for not much. I think the scanner will serve my needs (at least to start), but the problem is it didn't come with any film frames (yes the specs say it is transparency capable and it initially came with a 4x5 frame). Unfortunately I have been unable to turn up any used 4x5 frames on the net. So there's the back ground, here's my question, Do any of you have any experience in making film holders from scratch? Does anyone have a photo of a stock one or measurements I could use to duplicate?
I've been lurking here for a few weeks, and know the community here is so helpful and patient with us noobs. Thanks in advance for any advice.

The Epson V700 comes with film holders, but also a template for positioning things directly on the glass platen. When setting up a scan, there is a choice between "film holder" and "film area guide" which presumably tells the scanner where to set the lens focal plane. If the CanoScan is similar, you can simply lay your negative on the glass with the appropriate setting. If not, it might be worthwhile making cardboard spacers from different material thicknesses to see where the best focus occurs. (If you can't see any difference, it must not matter :) )

The Epson filmholders seem to serve mostly for holding the film flat (and secondarily for allowing repeated scans with a single set of marquees) but neither of these are likely to be important when starting out with polyester-base 4x5 film (which is pretty much everything currently on the market, I think).

Just a comment here - don't think you'll really get 4800 dpi scans with the Canoscan. Be very happy if you can get 2000 +/-. All of these small flatbeds have very "optimistic" specs.

Thanks for the advice Harold_4074, I'll definitely give this a try once I get my film from freestyle, it sounds like making my own holder is certainty possible. If I lay the film directly on the glass do you think I will have problems with Newton's rings?

Jim, don't worry, I'm not expecting too much from a 10 year old flatbed, for 135 I use a dedicated device from pacific image that produces good results if you know how to wrangle it, and a nice enough (but not 4x5 capable) V550 for 120. Let me tell you the Pacific Image scanner was not much more than the epson, but by way of specialization far outstrips the epson in quality.

try a google on 'APS film holders'

Good. I was concerned about how well it would work for smaller formats. I've scanned Minox 8 x 11mm on an Epson 750 and wasn't exactly blown away.