132230
Ok !!
sadly i couldn't use rmt...
instead, i'm made a .vgm file from a random generative script (again...), using dual c03051 ("pokey") as proposed (vgm uses 0xBB bytecode for using them, registers 0x00 to 0x0F for the first chip, and from 0x80 to 0x8F for the second one) - soon i hope being able to convert it to .sap (so this entry wouldn't be that "offtopic")
the script i used is at https://pastebin.com/raw/F8cRapLL - for the "patterns" there i used a kind of "medieval folcloric" sequence, like used on Angelo Branduardi's Alla Fiera Dell' Est, but simpler