technics format is proprietary, you can't load seq or panel memories from the laptop, and anyway it would probably be slower at midi transfer speeds. You can play midis, but would have had to save all the panel memory changes within the midi file track by track. Midi is a universal transfer format, not an easy play format.

Lag suggestions off the top of my head?
Call up the next song in the screen ready to load while the ending plays?
Only save required files instead of full performance saves to minimise load times?
Put seven or eight songs into one sequencer for auto medley play, virtually zero lag?
Use auto load and auto play on the HX6?
Remove empty measures at the end of a song for auto load since they just waste time before the end command? - this was covered in the 6k book etc.