I’ve been tri-amping for years and I’ll probably never go back to a single amp again. the biggest benefit (to me) is that none of the amps knows what the other amps are doing.
So, you can be playing along nice and loud and there is major bass all of a sudden, the mids and highs are unaffected.
Google "Marchand Electronics" all custom tailored to your spec.
Regards,
barts