Jarin, if you're lucky you might find a new old stock or lightly used Bosscreen for your camera. Improbable, but lightning does strike. That's how I got a NOS Bosscreen for my 4x5 Cambo.
I'm not sure, though, that you should want one. If mine is typical, they're not brighter than standard, they're finer grained so easier to focus. And don't forget that their thermal limits are narrow. Too hot and the wax melts. Too cold and it cracks. Either way, bye bye.