I get to use other peoples' mowers from time to time, and I've picked up the naughty habit of holding the "dead man's switch" bar in the "on" position with a twist of garden wire, so that I don't have to keep re-starting the engine.

*Ducks in anticipation of hail of rocks*

I definitely spend more time emptying the collecting bag than walking up and down.... wet grass is worst, it blocks up the vent. I use a stick to poke it out (as mentioned above, not somewhere you would want to stick your hand, ugh, shudder) to extend the time between emptying runs. I would not dream of using my hand to do this - not with any sort of mower. But a stick works well, and you can then squash the wet grass across to one side in the collecting bag. You can tell by the sound when the vent is becoming blocked, so you can poke it free before the mower starts leaving a trail of slabs of wet grass. And as the stick gradually wears down (a salutary reminder never to put your hand inside the vent) you just get a longer one.

I've encountered mowers with an electric start, but never one that actually works..... the batteries all seem to lose their ability to hold a charge.

If it helps, I discovered by accident that pull-starting left-handed is easier: I think it's because if you pull across the machine rather than straight up, you get a sort of "pulley" effect, plus your arm doesn't have to go as high in the air at the end of the pull, so it's less strain on the muscles. And yes, there is the possibility of damaging the cord, but if you use the wire twist trick, you only need to pull it once.

Good luck with your market research!

Rachel