It looks like BGResto has already done El Dorado, so you would not need to send him your backglass. Shay has done El Dorado also, and looks to have it in stock. Ron Webb (Homestead site) has not done El Dorado.

BGResto should be about $50 or so cheaper than Shay, but you will still likely have to wait about 10 weeks (or more?). You just email Steve to inquire and he will inform you what you need to do. If the wait is unacceptable to you, look into Shay, or possibly inquire with Mayfair. Also, be aware that the BGResto (bonded color film) method doesn't quite transmit light the same as the silkscreened method. Usually, the illuminated parts behind a BGResto glass will look slightly dimmer than the same parts behind a silkscreened glass. I went back to using #44 bulbs behind my (3) BGResto glasses.

I've used BGResto, Shay, and Ron Webb and appreciate all 3 being available.

One other comment, IMO, the silkscreen method does a little better job with reproducing saturated yellows than the bonded film method. YMMV.