Hi Tehya,
If your master is anything like my owner, I very much doubt if your comfort comes into the equation at all. LOL Anyway, have fun and don't be too Sammy when your belt is locked on you; it will be easy for him just to walk off with the key(s) and then you are in TROUBLE !!
As for what they did in the 'good old days', there is a feeling that chastity belts weren't around at all back in the days of the Crusades, and that the scenario of the knight locking up his wife before he rode off is just a lovely but fictional idea. Certainly the Musee in Paris which used to have a display of CBs apparently admitted that it was impossible to verify any of them as actually dating back to the Middle Ages.
For one, I would NOT like to have a hunk of rapidly rusting iron locked round my loins for any length of time; at least today's belts (at least the best ones) are made to measure and don't rust, but even so wearing one (sans plugs) all the time would be an unpleasant experience. Okay if it comes off now and then, but on all the time ???? Not my idea of a party !
Anyway, Sis, have fun, and let us know how you get on if and when your Master locks one of you..................
Love, Jane.