So here are the Mac #shenanigans I am getting into:
1) Swap out 128gig ssd to 480gig in 2011 #MacBookPro
2) Restore backup of #MacOSXsnowleopard
3) Set up partition to dual boot, hopefully, #macOSMonterey

While also:
4) Do fresh install of #macOSMavericks to the 2013 MBP
5) partition drive to dual boot Monterey.

Then I will have some old and “newish” OS to play around with both MBP
Status so far:
1) Successfully swapped out ssd in MBP11
2) Restored Snow Leopard on MBP11
3) MBP13 now dual boots Monterey and Mavericks. Maybe I should refer to it as the “mmMacbook Pro 13”

In process:
1) updating the dual boot on MBP11 to Monterey too. On the second partition I am starting with Lion and slowly working on up.
@jlw_the_jobber my 2013 MBP with the i5 does NOT like monterey. AT ALL. I could never quite figure out how to make it run not-awful. Best of luck to you.
@spaceraser It has worked fine for me; no notable issues. I ran it on the 13inch with the Core i5 🤷
@jlw_the_jobber huh. That’s my model.

Might experiment with it again.
@spaceraser I pretty much just use it for surfing the web and watching YouTube. Due to the low spots, I kind of gave up on gaming. So I haven’t really ran it through the paces; so that might be why I don’t know what is any issues with Monterey.
@jlw_the_jobber I’ve got my versions mixed up. Monterey was the latest stable version of MacOS I got to run on that mbp. I hacked on a version of Sonoma and THAT’S what gave the hardware fits.
@spaceraser Oh yeah, I was reading up that.  Anything after Monterey is glitchy AF; I think it’s due to Metal.