One pack per wheel.

One roll may be just enough to do one wheel.

Usually for road and off-road bikes there is only enough for one tyre per pack, hence why I have said previously they can be a bit expensive.

Saying that though - no punctures in over 13k miles this year due to penetrating road FOD on the road bearing surface.

NB: Only use this product for new or rarely used tyres because once stuck to the inner casing of the tyre it is nearly impossible to remove and is not that cost effective if the tyre needs to be replaced 3 months down the road due to it being worn out!

Road version weighs 50g per roll.

No, there will not be enough, personally I prefer the http://www.wiggle.co.uk/p/cycle/7/Slime_Atb_26_Inch_Tyre_Liner/5360009043/ because it does not stick to the tyre and can be re-used.

Yes this item would fit a 700x22 tyre.

I would not recommend using these for your tyres. You would need to apply them to your tyre side by side to get enough width which would leave a seam in the middle of your tyre for objects to pass through.

Yes it will fit but will be quite awkward to fit. In fact unless you are a person of patience I would get someone else to do it for you or dont buy it at all as this is not a miracle solution to punctures. You will stil get them.