well I don;t want to say it's a bad idea. it just might not be very well thought through. but I will offer a bit of advice:
1- I don't care how little pain you feel, even if you don't feel the initial cut you WILL feel it when you tighten the screws. I was awake and perfectly alert when getting 6 screws and a plate removed from my collar bone. The cutting is all peachy, but as soon as those screws are turned it's such a horrible deep-seated pain that goes right through you. No pain treatment is just dumb.
2- make sure you know what you're doing to prevent infection. some basic info for you; there are both gram positive and gram negative bacteria and they cover a vast spectrum that no individual disinfectant will cover. For instance isopropal doesn't work against most gram negative I think. The best disinfectant hands down is iodine. But a combination is ideal. For instance using chlorhexidine and iodine would be good. not just cleaning the area, but cleaning you tools and being in an incredibly sanitary environment is critical. the very last think you want is an infection.
3- whoever is sewing you back up, be it yourself or whoever, make sure they know what they're doing. have the, practice with meat or something.
4- bandaging is key for if you've followed through. Make sure to have proper bandaging. I'd recommend a simple gauze dressing with topical antibiotic followed by some padding/absorbent layer and topped off by hypafix. You absolutely do not want an infection.
5- look up a detailed anatomy of the shoulder. things can go wrong. easily. even if you've been cutting people open your whole life.
here's my shoulder after things DID go wrong in I think the exact surgery you're planning. and this was done by a 'professional'. this is what one would call a hematome.
good luck if you follow through