So, it turned out to be relatively painless to move to the DrawingSurface commands I mentioned before, but I have yet to fully test the upgraded modules at all game resolutions, which can often be the tricky bit to get working. Also, since my own site is on the same server as the AGS forums, I can't upload it right now anyway!
But to make sure the modules still work under 2.72 (and 2.71 and 2.70, where possible) I have to stick lots of
#ifnver 3.0in all over the place, to wrap up the version-specific code. And then, if you have to support versions before 2.72, then you need to wrap those up in
#ifdef AGS_SUPPORTS_IFVERas 2.71 and earlier didn't have the
#ifvercommands! So it can get quite convoluted. Then, I need to load up all the different versions and check they still work... Maintenance can be pretty non-trivial, sometimes.