Nice. So you will take the ace control box off when you do water hunting
Yip .... mix and match to meet the situation/requirements.
Possibly make the 350 display splashproof/waterptoof to 2 meters.
Wet sand up to knee deep water with small breaking waves .... splash proof will be sufficient ( just don't drop the unit or fall)
Final system with customized carbon-fibre shaft can have the ability for quick release/change for either unit.
Just a possible system for guys that have Garrett Ace or AT Pro units and Sea Hunters or other lose mounting PI units. Saves having to carry two full units around. ( Actually ending with two possible units, either sharing a common shaft the other unit carried in a backpac)