My opinion only...but arches on a 323 don't make sense to me, especially combined with davits, dinghy, etc. The weight alone will make the 323 squat and the bow will be pointed at the sky.
I just finished a cruise where I added two kayaks on either side of the cockpit. I also have a Monitor wind vane and a solar panel at the stern; tools, batteries, stern anchor, and fenders/lines in the cockpit lockers. Just with these items at the stern I needed to fill the bow water tank, move my dinghy and two bags of sails to the v-berth, and restow my trays of SS nuts, bolts, screws and other parts to the bow to get the 323 back on her lines. I can't imagine what would happen if arches, davits, dinghy, outboard, etc. were added.
Again, my opinion only.