I was thinking it would require 15* holders in that spot, but yes, the angle will be important to ensure a good fit, and to keep lines somewhat separate.
My initial thoughts would be that the two forward holders would go to the outrigger lines, and the rear holder would be the inside corner baits. Then i could add one in the tower leg for way way back. That gives 7 spots.
Track style as suggested would just not work for offshore use. Tuna and other pelagics would break those in a heartbeat.
I don't foresee fishing for giants with 80 or 130's in my future, so swivel holders may not be needed. Heaviest is likely to be 50 wides, but stand up for sure.
That sounds like a pretty good setup. The 15 degree holders should be easy to install between the stock locations. I’d suggest having a multitool/jigsaw and chisel handy to help with cutting the hole as the gunnel might be too thick for your hole saw bit to go through all at once.
Will you be running a center rigger for the WWB or straight off the rod tip?
When mounting the holders we sometimes use eye bolts for a tie down location; I’ve also used these on the underside of the gunnel for a cleaner installation:
Dog River Tools Stainless Steel Multi-Purpose Tie Down Anchor Strapping Hooks for Mounting in The Garage, Work Shop, Truck, Trailer, Golf Cart, Fence
https://www.amazon.com/dp/B07YNMGCBF/ref=cm_sw_r_cp_apip_Xp4DzFpMq7xtE
After installation you’ll need to play around with your outrigger rigging to add or minimize dropback as desired. You also might not need to double rig the outriggers if you pin the aft lines down to the stern cleats.
What ever you do, use the correct through-bolts and washers to reinforce the install. Don't be lazy and just run panhead machine screws into the cap.
Agree. Always through bolt rod holders.
If trolling with 50 wides I’d bite the bullet and pay for backing plates. Regular washers don’t provide much more surface area than nuts and fender washers often will not clear the rod holder tube.
Also make sure to seal all of the holes you make; might want to check the stock Grady White holders as well as the holes on mine weren’t sealed...