Hi,
I send messages to my helix then on to my mates MX5, no problem toggling blocks on and off, but not tried PC messages, I guess it must be able to handle these as the global settings have the option, my issue is how the paths are numbered in the mx5.
I get my mate to manually change his rig for the song then midi cc toggle on his pedals within his patch as the song plays,
will keep playing with this and report back. good luck.
EDIT: solved
On the rig you want to use, select hardware assign and give it a number.
then use this number to send program change (number you assigned) on the midi channel for the MX5.