Hi Robby, the filter is availible from here
http://www.maxmax.com/
the filter looks almost identical in colour to the glass I removed from the 350d
There shipping charge is expensive but I sent an email to Dan the owner and he will ship with USPS if you ask him too.
I don't use a custom white balance at all just the normal camera settings, the focus is alittle harder to get with autofocus, it looks slightly out of focus through the viewfinder but the image focus is fine, I think it's the extra glass from the filter that cause's it.
Manual focus is fine.
I cut my glass larger also then I used a grinding stone to trim it down, worked out ok just a bit more work.
David.