PVC tubes are easy to work with wet or dry sandpaper. I'd get a plastic bottle to wrap the sandpaper around, wet it then work those edges until you're happy with them.. Start with 100 grit (or 220 grit if the edges aren't bad, smooth them out then go to 320 and finish out with 400.. Once that form (the plastic bottle) has the edge shaped the way you want it, I'd just work each tube by hand without using the bottle, frequently dunking your sandpaper so that it continues to cut and not clog up.. Use a bit of masking tape around every tube so that only the tube is getting sanded... Once you have it the way you want it a coat or two of wax will keep it looking good long term...
Hope this helps - "Aren't boats fun?"

 

Google molson rod tube. Guy takes a Molson beer bottle and heats it with a heat gun and forms the pvc mouth it. Could possibly use a modified version.

 

I replaced a few of these on my old boat

Rod Tube End Flanges - T-H Marine Supplies

Fishing Rod Tube Ends - Organize and Protect Tapered Inside to Protect Rod Tips Use with T-H Marine rod tubes or PVC pipe Construct custom rod tubes for any application Mount your rod storage tubes in any compartment or bulkhead Flanges also serve as bulkhead passages for wires and hose Rod Tube...

thmarinesupplies.com

 

Thank you! Will take a look into all 3 of these.

 

rod tube finished edge

TRIM RING-Marine Town FISHING ROD STORAGE COVER-Marine Town

www.microskiff.com

 

What did you come up with ?