Thank you - these parts are so very delicate so it's not surprising that after many decades and however many services that they break. The one I have is slightly fractured and a bit of a twist at the fracture as well. I wonder if there's a way to repair it? I fear that an attempt to solder it will just cause it to break from the heat.  This is the exact same watch as Mark's video: https://www.youtube.com/watch?v=pFOQm9sAzE8&t=932s. He runs into the exact same issue. Mark chose to make a replacement and was kind enough to record the whole process. I am leaning towards doing the same. In Mark's replacement, I do not believe that he created the alignment pins to the part. I am curious as to whether or not this is a concern as I would not want the jumper to move over time. I was thinking about ensuring the new part was in very close proximity to the balance cock and/or the chrono bridge to prevent rotation.    

Most of the cylinder watches are not worth a lot.. to be fair, some are quite nice but many are not, and as said, most repairers don't repair them. Over in the UK it's not so easy to sell a cylinder pocket watch to a dealer - working or not.. it seems people just don't want them for the most part. A gold example is nicer but still not highly prized unless particularly rare or special. Rare would be something early/ fitted with a ruby cylinder / a watch with a complication. I've got a load of cylinder watches but most don't work and aren't worth repairing (the working ones are often terrible timekeepers by modern standards - maybe 10 minutes a day) - one or two would be pretty enough to make a nice gift for someone who's just into that sort of thing.   The watch in your pictures is actually sort of nice but the gold price is really high at the moment so it may be more expensive than that type of watch may usually dictate - due to the gold content.

Hi and welcome to the happy factory

Cylinder escapement discussed here  

Welcome here and if you could take the time to post pictures and details of your makings that would be certainly very appreciated.