Thanks! I wish I had some rod holders in the back. I have a huge fishbox, and between the engines that come up against the transom no space for a rack of rod holders..
I have F300s, so for me there was no problem putting a 5 rod holder across the back and I troll from the center holder between the motors. (I cannot, however, tilt my motors up with rods in them or they would hit the reels)
However, you still have plenty of room for 3 or even 5 rod holders - one center mounted between the engines, and one or two on the transom door and on the port side. I wouldn't troll off anything attached to the transom door for obvious reasons, but for storage it would work fine. Otherwise, an up-and-over solution should work and clear the motors, a local fabricator should be able to make something for you.
Interesting that you only have 4 on the hardtop piping? I have 6 on my older 330. Also, some folks have put drop racks across the top of the hardtop - challenge of course being that you need a way to get the rods out that high up.
But to answer your actual question - I think you have room but only you will be able to tell exactly what you want to work around. Personally I prefer the cockpit open. Why not mock it up with some plywood?