@Colin *******
you sadly failed to do your homework. Staying only 55 days is a no brainer.
...Arrive into Thailand... Visa exempt on arrival..gets you 30 days stamp.
...stay one night in a hotel..
...ask hotel for screenshot of the TM30 they filed.
...go to Thai immigration office at IT Square in Bangkok on the NEXT day to get the 30 day extension of stay... ...
...then travel to your home
No need to return to Bangkok for the 30 day extension of stay.