Adam -
Hard to say. Slotting the bottom portion (w/relief holes) is much easier but not as clean looking since some of the slot will remain above the existing Hobie holder due to lack of compression where the slot ends.
Grinding down the bottom section of the tube makes for a better looking holder but is labor intensive. Also doesn't leave a whole lot of wall thickness.
Not sure which would be stronger - need some testing or I'd just be guessing.
A personal choice. I made the slotted version first and knew I would work on some improvements, however minor. The next version will use ABS pipe which will eliminate painting and have the ability to float (ABS floats, PVC sinks). My $.02 - make a slotted version first and make a more permanent version when you figure out exactly what you want. The tubing is cheap...
Almost forgot - I use these little spring loaded rope locks for the adjustable swing cord, about 59 cents or so for two at Walmart in the camping section. Still working after months and hasn't rusted yet.
Something to do while we're all getting "cabin fever" from the rain. Time to rebuild a few reels...
