Best practice for mixing movement parts

I made a low ball offer on this Seamaster (ref. 14384) with an incomplete movement on eBay somewhat impulsively, way too late at night, based on blurry photos, as a noob does. I was confused a couple of days later when I was notified that my offer was accepted because I didn't even remember making it. After weeks of regret, the watch arrived, and I was pleasantly surprised by the dial and most of the case. I meanwhile purchased another working but incomplete cal. 610 movement, and thankfully the parts it lacked (setting lever spring and sweep second pinion) were present in the original movement. After a few hours of work I now have a complete working watch that I'm really enjoying plus about 3/4 of another movement.

I will soon clean and lubricate it, and I wonder what is the best practice for deciding which movement parts to use when reassembling it? Should I use as much of the original movement as possible, or try to select the best part available? If I use all of the original movement, the mix will definitely be apparent because the colors differ, and at least one bridge, the balance cock, and most of the train of wheels needs to be replaced.

I'm leaning towards using mostly the replacement movement and making that clear if I ever sell it, but I thought it was best to ask the experts. Thanks as always for any advice.

Thanks for the advice. Do you mean that I should try to keep the original barrel bridge as part of the reassembled movement, or just that I should hang onto it to keep with the watch if I ever sell it?

If the reason for swapping the balance bridge is due to the semi rusted metal parts.

Just swap the metal parts from the other bridge

Is there a reason to swap out parts of the going train?

If you try to sell it with mis-matched colored bridges. People will spot it and most like not read anything written. Will write it off as a frakenwatch

Only time is when a part is damaged enough to be un-useable

DON

The only reason I had to consider mixing the movements was to use parts that were original to the case and dial as much as possible - all but two small parts currently in the case were from another movement. But if I did try to use original parts for the sake of originality, then it would be an obvious mix of movements. Same caliber and OEM, but nonetheless it would set off alarm bells like you say.

I think that some of the answer here depends on your goal for the piece. If you are going to wear and enjoy it, the answer might be different than if you are going to put it up for sale right away. Since the donor you bought is the same caliber, but was more complete, I personally would use it as you have already, but swap out all the best individual components. You could keep the original incomplete movement, now also minus the setting lever spring and sweep second pinion, with it if you sell it.