if you have a spare roll of wallpaper (or similar) just paste it to the glass you plan to remove/ break a few days beforehand.
When/if you break it there will be far fewer loose fragments to deal with.
IIRC you can buy Kevlar reinforced gloves which may help you avoid cuts when handling the fragments.
If you can remove most of the putty you will probably find tiny brads (nails) which retain the glass prior to the putty being used. Often in old windows these have rusted away, so don't obstruct the glass greatly.
If you make up a piece of laminated plywood (so the total thickness is two or three inches) of the correct size, you may find that you can make a 'pusher' which, when struck, stands some chance of pushing each piece of glass out of the framework wholesale. It may still fall down and break, but at least the wooden parts will have fewer bits of jaggy broken glass stuck in them, so will be easier to deal with.
cheers