You could also use the pin style that way you could remove the seat when not using the boat. Its going to put you up about 3" or so higher than the swivel base.
I have drilled them out from both sides depending on where I could get my drill into. The inside is definatly easier b/c of it being flat and not having to drill a pilot hole to keep the bit center.
Not to crush your hopes but coming from experience its going to be extremely tipsy. Just put the boat in the water and stand on the bench seat as a test. Plus the added weight of deck materials, fishing gear, and another passenger will make it rather heavy. just a though.
For the rivets you can try rebucking them and then adding some silicone (3m 5200 is preferred). With the 9.9 the rivets may continue leaking from the flexing of the hull. You want to use stainless steel screws for attaching the floor to the ribs. Don't go too high with the floor that boat...
Welcome. Can't wait to see some pictures of the beast. Do a little searching around and you will find all you ever needed in relation to painting and decking a jon. Good Luck
How many accessories and how often are you going to be using those accessories? If you only running your lights and a bilge and those are only going to be on for a short time you should be ok with your TM battery. If your going to have several accessories (radio, depth finder, lights, bilge...
The "horizontal H's" represent your switch or the break in the circuit. All the switch does is break the circuit of the item.
---beat me to it zum
Ober using a fuse block and switch panel will do the same thing as the prefab switch panel.
Try this link https://www.tinboats.net/forum/viewtopic.php?f=5&t=9070
Also you might consider getting a negative buss block to run all of your negative leads to so that you only have one wire connecting to the battery.