'' a G clamp is much easier and smaller so you can carry one with you''

I agree a g clamp would be better, I must get one that fits as you are right it would be easier to carry.
The 2 clamps I have would not fit, one was too small to get over the tyre and the other didnt have enough thread to push the soft walled tyre out the groove.

I think the video shows a good technique for getting those stubborn tyres off the bead whether its a block of wood/fence post or tools you have at hand.