That is also a great looking build, Grant!
With regard to the 50mm bridge conundrum, they are indeed difficult to find in an F-style bridge. I found exactly one:
https://www.stewmac.com/parts-and-ha...AaArolEALw_wcB
Seems like a lot of $$$. So cheapskate that I am, the way I'd be tempted to do it would be to get a set of pressed saddles...
...and cut a small notch with a file where I want the spacing to be.
Meanwhile, the lazy part of me would remind the cheapskate that it sounds good and has a nice clean look just as it is and it ain't broke... ;-)