Holton Bb 6/4 Bells, Leadpipes and 5th Valves

[Peach]

Ideally looking for actual experience with these things more than hopefully opinions (but they're welcome too!)...

1). Any folks tried modern leadpipes with these horns - like the MW45slp pipe which is a popular mod to 2165's? The one I have is the original - needs a little work but it should go back on ok. That's where I'll start at least.

2). Anyone had a 5th added (independent) and could comment on the change in response etc.? I know Fletcher mentions having a 5th removed on one of his Holtons and liked the response better. His opinion is very valid but looking for others - I'm lazy and would prefer a 5th if it's not going to screw things up too much.

3). This thing has a removable bell-front. I'd really like an upright - also removable - to go with it. I've contacted Lee Stofer about the Kanstul bells for Conn & Martin bell-fronts to see if they'd fit (inside Dia. female tenon 210mm). Other option is to get a complete upright bell for it - I've looked at Chris Olka's damaged Deck bell and will contact him about it. Any other options possible??

Thanks for any insight!
MP
PS. Yes, this was Mike J's Holton.