Thanks for weighing in! Did the larger sizes look weird because of the slope of the fretboard and neck, or was it something else?
I just felt they started looking over sized, given the width of the dark fingerboard edge on my instrument. You are drilling out the edge of a 4-6mm fingerboard, and when you have the contrast of blonde maple neck against that dark strip, you'll find it looks best centered. There is the risk of chipping out that brittle edge by boring too large a hole. At 2mm diameter, you're only leaving about 1.5-2mm either side.
Make sure you're using a fresh new drill bit. I started by drilling out the original 1.5mm with a 1/16" bit, then enlarged with a 5/64" for clean results. Those 2mm rods fit like a glove - just dip the end in medium viscosity CA glue, wipe residue/squeeze out promptly. Mask the area, flush cut the rod off, pull tape, sharp chisel to smooth/fair the cut edge. Ran full length of fingerboard edge with ~320-400 grit paper for final smooth/leveling. A little bit of Watco or similar wiping varnish quickly restores the sealed look of that edge. I did a final buff with gray scotch pad, as I wanted to dull down the gloss for a smoother feel, as so many of us do. Pretty much a factory installed appearance.
That dark fingerboard changes the argument for rings, IMHO. After using the solid, non-ringed version, I'm very glad the glow is from the
entire dot, as again, its
just enough to make a difference. When first charged, you'd think they're LED's, but rapidly dim down to a much subtler glow.
I totally get the black ring on an all maple neck/fingerboard, but you do need to think a little differently on the dark stuff, as you want it 100% white or 100% glow, IMHO. High contrast is the whole idea.
On my instrument, the inactive, uncharged/glowing dots are almost exactly the color of the original white dots they replaced, so they simply got a pinch better by upsizing 30% from 1.5 to 2mm. It seems so insignificant, yet it does make a difference under daylight as well as under dim lighting when you need a glancing reference.
Good luck - I still say it's worth doing.