Ok, maybe I made a working combo of 512 KB Kickstart plus 512 KB Extended ROM, at least, WinUAE does load it and if I boot with no startup-sequence, well, the workbench.library I put into the Extended ROM is correctly seen (I removed the one from LIBS drawer of course).
Now if I want to try burning the files into EPROM, which one should be first, the KS code or Extended code?
As for the bases, I left F80000 for KS and used E00000 for Extended, is this right?