You don't lose any kite size with different line length, the only thing that changes is the size of the wind window. So if you do a full power stroke from top to bottom on 24m lines vs 22m lines, the distance the kite travels will be different. If you are properly powered you probably won't be doing top to bottom sines anyway, so it makes very little difference
kite reactivity might be noticeable. i notice a slight difference between 20m and 23m lines, especially when looping the kite
Longer lines mean more power, all things being equal. Its a matter of centripetal force components.
That is, if on 22M lines with max sines in marginal winds you are barely able to go upwind, you will probably manage to go upwind on 24M + lines.
Obviously you loose in reactivity.
For me no fun in either cases anyway...so i would say keep reactivity and go for a bigger kite size.