Split focus for M645 1000s

[Martytoof]

I picked up a Mamiya 645 1000s for next to nothing, with a metered prism and 55mm 2.8, but I'm not very happy with the stock matte focus screen. I've missed a lot of shots in somewhat dim light situations and I think I'd like to go the route of my Pentax K10d and add a split focus screen.

Are there any more reputable sources than eBay? I've seen the screen go for as little as $40 on some auctions, but I'm always weary of knockoffs or whatnot. If anyone has any experience with a particular eBay seller's focus screens on their M645 I'd love to hear it.

Thanks!

[Nesster]

http://www.keh.com/OnLineStore/ProductList.aspx?Mode=&item=0&ActivateTOC2=&BC=MS&BCC=5&ID=46&CC=15&CCC=27&BCL=&GBC=&GCC=

about as reputable as it gets... though the shipping charges do add to the total

[Martytoof]

Thanks very much. Not sure why I *always* forget about KEH, considering that's probably the first place I should be looking.