make sure the TM will clear the rod holder which ever way you go by deploying and stowing the TM BEFORE you start drilling. I mounted a 2 rod holder on the bow of my Tracker, does not interfere with the TM and don't have to move/rotate the rod holder either. I only use 2 rods (lazy) and longline 99% of the time, I can LL from the front or back of the boat as I have a 4 rod holder mounted where the rear elevated seat mount is.
I would go fishing in the garage or back yard, sit in the boat, and see what works for you by moving the rod holders around, deploying the TM, see if you can reach all the rods as needed, go thru every motion you can think of as if you were out on the water. That way you'll have a better chance of getting it right the first time. since you don't have carpet, the holes will show from that 1st attempt.
I know you stated you did not want to mount the holder on the gunnel, but consider that location on the bow by just placing the holder up there and see how it works, you may or may not like it. The rods are out front where they need to be, won't take up floor space, etc.
Better order an Ipilot as well. LOL
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.