For me, neither. I have a 1652, but I also fish a lot with a co-angler or sometimes a dad and son. If you fish alone, 1456. If you fish and your wife or buddy just wants to hang out and not fish, 1646. If you plan to have two 6 foot people swinging bait casters trolling up a bank, go wider. I...
I agree with the OP, stop chasing the plugs. Both numbers are correct for that engine. The timing of your plug change could be a coincidence.
Watch water pressure when the alarm hits - low PSI possibly? Check the impellers or consider the complete water pump rebuild kits and new thermostats...
As someone who owns and operates a professional marine fuel injector service shop, the issues with *new* knock off injectors is 100% real. I know it's tempting to buy knock offs at a discount. Even if the fuel injectors spray well and are flow matched to your existing set, you just don't know...