The biggest difference as to how the panel will react to being sand blasted is the amount of compound curvature present,
'Tight' panels with a lot of curvature, like '30s and '40s fat fenders, and inner panels that have strengthening ribs, will usually not exhibit any noticeable distortion after blasting.
But the large low crown exterior panels common to later model cars can be warped in a matter of seconds, I managed to destroy 2 nice 1960 Chevy hoods in just lightly sandblasting a few freckles of rust off the inside, after that frustrating experience I now only use careful hand sanding to remove rust from low crown panels, this is especially important if there is any inner bracing of the panel that cannot be easily removed (like on a '60 chevy hood)
On 'tight' panels like my old '48 Studebaker truck blasting works fast and the metal can be cleaned to the point called 'metal in white' that is as clean as it will go, this however is NOT advisable, as such harsh blasting peens the metal and work hardens it, making it brittle and prone to developing stress cracks.
Because of this I do not use blasting as a means of paint removal, I first remove all paint with a chemical stripper then use the minimum amount of blasting that will remove the 'loose' rust, if it is absolutely necessary to remove more rust beyond this point I employ the DA , hand sanding or a chemical rust remover.
However as I posted in the thread 'RUST...' I prefer on most interior or hidden panels to leave a thin even film of rust and coat with a 'Moisture Cure' coating.