I should probably mention that my sticks are mounted into 1x Poplar.
I don't hang off of them, but they definitely get a workout.
I haven't had any problems with them coming loose, or anything in the six months, or so, that they've been on.
If you do go with T-nuts, countersink them slightly, run the bolts all the way up flush with the top of the T-nut, fill the top with putty, and sand it flush with a sanding block or orbital sander.
That will keep the putty out of the thread area on the T-nuts.
As long as you use bolts that are too short to hit the putty with the stick mounted, you shouldn't have any problem with the putty coming loose, or showing a depression.