I too have a ‘pistol shirt’ like that & does a great job hiding a full size handgun ( HK USP .40, Sig 229 .40, Browning BDM 9mm, etc for a size idea ) BUT plan on sweating more than normal wearing it. It’s what I wear to weddings & other formal type events when I peel my suit coat jacket. I leave a few short buttons undone that’re covered by my tie clipped tie. Allows quicker access but this way isnt a quick draw setup at all but does beat it being in a vehicle out of ur control & custody. Get ANY lockbox w/ a steel cable that you loop around your bottom seat frame when you leave ur piece/s behind. Tomorrow or sooner - think how mad you will be when, not if, it happens- plus it adds to the criminals having one more gun to do bad things with - not the sorta thing u want on ur conscience either.
Oh, & welcome from chilly western NY, Kaktus Jaque - only 21F w/ wind chill down to 11F. Wanna trade ??