Hi Rob, there are a few threads about this in the APUG archives. I haven't experienced scratching of the negs while loading them into my tanks. There is a great article on using unicolor drums with 4x5 film over at http://largeformatphotography.info You can use small cloths pins to seperate your negs. I wouldn't open the tank under safelight until I had at least some fixer in the tank.
Also, you might want to check out ebay for a uniroller. It will help with keeping your negs consistent.