Truth be told it can be really hard to dodge online, because of the lag, who’s host and all that jazz.
As far as timing goes, I wouldn’t try to dodge a lighting strike with just one burst of jetpack because of the lag and radius of the strike.
How to dodge it? As some people have mentioned going towards the Kraken is your best bet. If you cant do that, try to get some visual obscurity in between you and the Kraken (A tree, a house, a rock, anything)
Conserve Jetpack! I dont use my fuel against a Kraken except to dodge lighting strike and vortex. I shoot mines, strife normal attacks, and jetpack everything else. This will insure you dont get caught with your pants down with empty or one bar of jetpack.
Save your jetpack for the lighting strike and vortex (Because vortex can combo into lighting strike). 3 bursts of jetpack always works to evade the strike