Ok, pity the homebrew didn't work out
There aren't many who haven't succeded.
Not sure about sparta (I'm not a sparta-guy) but with SDX you can make a config-file
that tells SDX not to use OS-RAM. With the 256k machine you have the most chance
then, since you can tell to use BANKED memory, giving as most as possible RAM for
the user.
I'm not behind my own PC, otherwise I could list you the config content.
Back on line next Sunday.
In the meantime, check out the manual for sparta or SDX?
Grtz,
Sijmen.