have had fuel and octanes since 06 they are set up to launch off the fifth line as it halves the wing distance and they drag the other half of the kite to the edge of launching window. older 4 line( started with 13 metre diesel) uses the full width of the canopy were bitches for most things including launch.
I still think that the one line set up was very practical and allows you to Depower (flatten profile and increase top wind range) and cleat fifth line on the water, and are much easier to re launch even if leading edge pressure is low.
reverse launches in really light wind much harder to impossible without fifth.
the new rally, good to self launch and land , trucks much higher into the wind more stable than my old fuel but the power is not the same

its all techique apparently