I stuffed blue tac into the back seams after I loaded the cassette; no leaks this time. I didn't even bother taping the 110 cassette back together.
The viability of reloading 110 cassettes really depends on what camera you have. An unmodified Mk II requires the perf be detected to enable the shutter which rules out unperfed stock. No need to notch the cassette, however. I'm under the impression that the Mk I model is more convenient for reloads, but I don't know the specifics. If I know I want a clean frame for some reason, I can always just do 2 advances with the Mk II. The end of the film is indicated by the shutter no longer cocking, kinda like the mechanism in a Pentax 67 (which takes the same battery as the Mk II btw).
The killer feature of this camera for me is the lens. Wider and faster would be great, but the macro mode used hand-held is a joy if that's your wont. The composition reminds me of the action from a Nikkor 30-110 on tubes I used with my Nikon 1 bodies before that lens' aperture blades went kaput. Working distance is set by the zoom ring with 25mm giving the most magnification at the closest distance. I keep the focus on infinity most of the time but it can be used for a small amount of fine focus if you need to nail a particular framing.
I can get similar results from my 16mm cameras using accessory lenses but none of them are SLRs. 16mm is still more compact and convenient but it's nice to have the option of the advanced features on the MK II. No lenses to collect and I haven't even used the self-timer yet.
Edit: Still tough using 500T @ 400 handheld in low light. The next cassette I split I'll modify for 400 speed metering.