ok, a few developments.
i figured if i was going to make any headway, i would need a control machine.
so i sourced an Atari-VGA monochrome cable and fired up the MSTE.
the Epson SMD-380 that was on the MSTE is working but is 720k, not 1.44mb... so my MSTE is a 720k version.
i don´t know how i was so sure it was a 1.44mb drive, i could even swear i had read info on the web about it, but sometimes the web information available is generic to the epson series SMD-"300" which includes both DD and HD drives.
anyway, so the 720k floppy works on the MSTE with both the MSTE FDD IC and the TT IC.
i ended up switching back the MSTE IC because i wasn´t sure it was HD compatible with the TT.
the TT with it´s HD IC does not read or format 720k floppies.
the sony MFP-920 floppies also do not work on the MSTE, but maybe the system just does not accept HD drives, even with the TT FDD IC. i vaguely remember that some other modifications might be needed. so those are still in unknown condition. the TT HD FDD drive wasn´t tried on the MSTE because it´s just a bunch of parts for now while it´s being cleaned.
due to temporary misplacement of IC removal tool, i ended up removing and inserting the FDD ICs several times with less than optimal tools (flat screwdriver and/or thin blade) which led to several pins being bent
so i don´t think i should be removing those again unless it´s to replace them!
so, limited to ST-HIGH on the MSTE, armed with a new set of 720k floppies (10€, 10 discs), i removed the HDD from the TT, connnected it to the MSTE and proceeded to spend some time passing software from the PC to the MSTE, floppy by floppy. no problems besides being limited to 720k.
have a NetUSBee and was looking at the installation steps, but a link to a needed STX file was not working and seeing that i would need a specific PC with a static IP address and my network is a mess right now, i stopped it until had more time to spend.
i went to the site:
got a list of my favourite games:
NEW ZEALAND STORY
and then put the HDD back on the TT, tried to run several of the games, but no luck. they all bombed out (2 bombs).
i only spent a few minutes, so i might be missing something. for example, DM with with start option bombs, with another runs and opens until i try to select the first warrior.
i have also received some 1MB 30 pin SIMMs, so i´ll be able to test the TT RAM board.
again thank you for all the help!
(credit to Urban on this)