No danger of of gashing your hand and no need to have a mate helping - use a third hand:
My other top tip is to use the weight of the car to undo the crankshaft nut: jack up the car, put the socket on the nut with the tip of the breaker bar on the floor then lower the car
I still prefer having a proper tool for the job myself. I've seen all the various tricks but personally I'd just like to lock it solid so I know I've got peace of mind then I just use a breaker (or a torque wrench when it goes back on again). I am slightly spoiled with an SV which makes whipping the starter on and off a doddle, no issues with wiggling it around the primaries.
Quite useful when you've got an engine on a stand too:
If you're changing the clutch or flywheel and you crane the engine out into the floor, the tool will bolt across the two upper bellhousing mounts too and hold everything still while you do the clutch or flywheel bolts.
SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm
Wedging a screwdriver in the ring gear has worked for me single handed on over 200 Caterhams and around 100 Elises, an alternative as long as you dont have a lightweight flywheel is to use a length of round bar (12mm or so) through the hole where the crank sensor fits and push it into the crank sensor holes. Or the method with a screwdriver and mole grips on the induction side of the engine on the wing of the engine ladder.
If you have a flywheel which has the position sensor it is possible to remove the sensor and put a suitably shaped piece of 16mm bar through the hole left by the sensor and into the front of the flywheel into one of the machined recesses. I made mine from stainless but mild steel would be fine.
Very safe and reliable one in place.
Just be careful if you have a lightweight flywheel as these do not have the same machined recesses, they have raised spurs which will snap off if used to lock the flywheel.