As other noted the tubing (mine is 3/8”) just connects from the cupholders to “impact drains” (west marine etc. sells them, 3/8” by 1-1/2” is what I needed) that allow water to drain onto the deck then out the scuppers.
As for accessibility, the helm cup holder tubing and drains can be accessed via the access hatch in the cabin. At least on the 2011 336, imo, those are the only critical drains to make sure you have to keep water off electronic wiring, electronic box actuator, and condenser. The other cupholders would just drain directly into the bilge if you didn’t install tubing, so it might not be worth the hassle to you, as some of that access can be tighter, but was doable for me.