modify deardorff back to fit eastman No.1?

I purchased what was supposedly a deardrof 8x10 back thinking that backs were pretty standardized and that it'd fit on my Eastman No.1.

It does not. the interior lip that fits inside the rear standard is 1/16 to 1/32 to wide, both ways, and the overall width is about 1/4 inch too wide to fit in the clips - so,

Should I take out the chisels and start working the "deardorff" back to fit? or should I try to see if there's anyone to trade with?

I'd hate to irreversibly modify something that I shouldn't , but on the other hand, I really want to shoot some 8x10's of me family this christmas.

With a week to go, you're toast.

Don't rush this, and you really don't want to kill a Deardorff back.

Give yourself time to find the right back, and sell or trade the Deardorff back.

Where do you live ?

I live in Houston - Here are some photos of what I'm looking at.
http://s266.photobucket.com/albums/ii261/mrexplodo/party/

The camera is 11 and 1/16th square with room for 1/4 inch overhang, while the 8x10 back is 11 and 3/16ths with 3/8ths overhang.

Be easy to do with a routertable.
take it down, refinish & no one will know it came from a Deardorff if you don't give away the secret.