My advice would be to take special care when choosing the rail. A cheap rail can add significant weight to what should be a lighter build. Combined with a pencil or LW barrel you’ll reap the benefits of mobility in a shortened package. I own both 7.5” and 10.5” ARs, each with a specific defensive purpose and both are well suited IMO to their role.
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Your timing leaves much to be desired given current prices and availability so you may wish to piecemeal your project beginning with a stripped lower as previously mentioned.
Might I also suggest inquiring with your insurance carrier about a newer cpap machine. They are both smaller and quieter than older models, which could in turn allow you and the Mrs to again share a space.
https://www.easybreathe.com/AirSense-10-Autoset-with-HumidAir-and-ClimateLineAir-Tube-p4361.html It’s money well spent if you need it.