There's thread at atariage about how much free RAM is available after booting from image, surely without AUTO run PRGs, ACCessories or any other RAM allocating SW.
I wrote about it long time ago on page: Playfhd (https://atari.8bitchip.info/playfhd.html)
Can see it at middle of page. TOS 1.02 is not listed, and it uses more RAM than later 1.04 .
Below it is detailed RAM usage .
All it was there in 2009 already.
Hehehe, people should visit your site more often. :D