try medly play for the 10 songs in the sequencer, minimal delay if there are no start and stop pauses in the sequences.

you can navigate the hard disk while a song plays so have the next ready to press the load button as soon as the end of the previous song fades - 2 second delay.

Or use custom load scripts with auto start and auto load - again the 2 second delay, but no limit on the position of the songs you can program.

the only other way would be to have 2 sequencers like the pa80.