I understand. The standard charset still gets copied when we enter hires but if I don't use the std chars I can use that memory for something else. Got it (just have to ensure i print attribute 9).That means that the whole standard charset area is available for your own code or data, of course if you try to print any text it's going to be garbled, but it's just a matter of using the attribute 9 at the start of the line, and there you go: You are using the second charset instead.
I now also understand about the osdkaddr. If i used TAP2DSK (so it could run as a disk image on say, the cumulus) it wouldn't work if I used $400 (as DOS gets trashed). Using $400 would free more memory but it would be restricted to tape only. Is that summary correct?
Lots to think about...
Fixed yesterdays problem 100%. Later today I'll work on another hole in the AI using the newly freed memory (I think I'll be happy then)