@gwpt
Have a good new week start!
Generally, both will work fine and you should be 99.5% good with the original variant!
But one small adaptation (4p503) fixed a problem in the original SEQ v4+ in conjunction with the MatriX, which may be relevant:
SEQ v4+/503 release - fixes to allow octave switching via ALT key in BLM/MatriX mode
So, using the 503 variant will give you vertical octave switching with MatriX, which may be a good thing.
Best regards,
Peter