Points are preferred for Marine use simply because if/when they take a crap (which isn't often) you can have it back up and running in a few minutes.
I recommend installing a set of points into the distributor for each engine, set the dwell, then remove them, seal in zip lock bag with new condensors and put them in the boats storage box in the console.
Install another new set of points/condenser, set the dwell, ignition timing, and sleep better at night.
If/when they take a dump you'll be back up in minutes, and don't forget a good fitting screwdriver on board in your tool kit or put one in the bag with the spare points. If you have the type of distributor where you have to completely remove the screws than hold down the points/condenser grab a few extras and put them in the back with the spare parts. Most of those screws will be #8 or #10 and either 24 or 32 pitch. You can get a hole bag of them for a couple bucks at most fastener stores.
I'm not fond of electronic conversion kits, even for automotive use. You will NEVER break down in front of Summit or Jegs and require a flat bed back to the house. Contrary to what companies selling "bug zapping" distributors will tell you, there isn't a single ounce of power waiting for you by converting them. You may get a little quicker cold starts with MSD stuff, and slightly improved idle quality IF your carb is a little lean at idle, but from idle to the shift point they make the same power as anything else provided the timing curves are exactly the same.
With a boat you can get stranded miles from the dock and become a SAR case, or even get injured or killed if a storm comes up or you get ran over by a barge.
I was a Coast Guard boarding officer for several decades. As far as inspections and carriage requirements we typically only look at the flame arrestor to make sure it's still in place, and a working ventilation fan for enclosed engine compartments on small craft as far as the engine bay is concerned. So you woln't get a violation for converting your points distributor to electronic or replacing it with something aftermarket, but as mentioned it's not a good idea......Cliff