I'm almost done with this! (for now...)
I manufactured a brace to connect the receiver to the bell using brass rod, and the whole leadpipe is off the bell. I noticed there's a lot of "ring" in the bell after I release a note. I've only played it in my basement, so I'll have to wait and see how it sounds in a larger space.
I got the new, longer ferrules soldered to the crook (I still need to put the brace back in between). I found that if I use a sousaphone bit, I only have to have the slide pulled out about 3/4" to play it in tune (without the bit I still need to pull a good 2" which puts the slide way beyond the bottom bow). It also makes it more comfortable to hold on my lap, so I think the bit will stay!
I was hoping to play it in the orchestra this week, but I forgot about parent-teacher conferences, so it will have to wait until next week.
Once the brace is back on the main slide that should be all for a while! I've got a Cronkhite gig bag on order for it and I'll be set!