I've been practising with Mabel a fair bit recently, partly because we haven't been doing much real handbell ringing over the summer. Here are some thoughts on how I use it. It would be interesting to hear from other users.

• When Graham John developed his handbell manager software, enabling hand-held motion sensors to be used with Abel (and Beltower, but I haven't used Beltower myself so I won't say any more about it), I bought a pair of sensors and did a lot of ringing with them. It took me a while to get used to it, partly because the sensors are much lighter than handbells. I never tried to build the sensors into something more like a dummy handbell. Later, I installed Mabel on my MacBook, and meanwhile one of my motion sensors seems to have stopped working. These days I just practise with Mabel, using the press/release key option (i.e. press for backstroke, release for hand stroke). Now that I've got used to that, I find it quite acceptable, although if anyone develops something similar to handbell manager for the Mac, I will give it a try.
• I don't use Mobel (the iPhone version) much, partly because I nearly always have my MacBook handy, and partly because it doesn't have the press/release option. Tina seems to use Mobel much more than Mabel.
• I don't find it helpful to look at the bell images on the screen. While ringing, I either close my eyes or look away from the screen. If I get lost, I sometimes look at the display of the changes, but usually I just stop and start again.
• In order to have as familiar an environment as possible, I set the tenor note to C, because that's what we usually ring.
• My ideal ringing speed is based on the regulation Imperial College peal speed of 2.24 for Major. However, I find that when I only have the sound, and there's nothing to look at, 2.24 feels rather slow. So I usually set the peal speed on Mabel to 2.10 for Major, unless I'm trying to ring something very difficult that needs more thinking time.
• I don't aim for perfect striking, although of course I try to ring with a good rhythm. Mabel doesn't have the striking measurement option that Abel has. What I try to do is keep up with the ringing without getting lost in the method, and to put my bells in the correct spaces without audible clips.
• I find it useful to practise conducting, in the following way. I program in a composition (for example a peal of 8-spliced, our current project) and then practise transposing the coursing orders while I ring (usually the tenors). Coming up to each lead end, I use the coursing order to work out which place bells 3-4 or 5-6 are going to become, then look at the screen to check that I got it right.
• Sometimes one of the children comes into the room and starts talking to me. In this case I try to keep ringing for as long as possible while answering whatever the question is; good practice for unexpected incidents during real ringing.