Heya Grog
Yeah you can - though many Pimps will say otherwise...
Most kites these days are of equal line lengths.
The obvious variatons are..
1. Bar throw for depower
2. amount of adjustable depower
3. above or below bar depower
4. front & rear line adustment at bar
If the throw on a bar is shorter than original - it may not roll over for relaunch as well, and if it is longer it may roll forwards when you let the bar out...
If you want a faster turning kite, use a wider bar or use shorter lines or both. Shorter lines will lose a little bottom end but increase top end, a fair trade i think.
As long as you tune your bar/kite combination - all will be good and is an important skill to have, to get the best out of any kite.
Cheers