Kalista helped me reach plat 1 in no time. 72% wins out of 80 games and least obvious adc, you can carry lane easily even if your support is potato.
Any kalista script should do the job as long as you can see amount of damage your E will do.
i personally used xcosft All in one for L# but Kite machine kalista(BoL) seems pretty neat aswell.
As kalista you are a huge bully, what you want to do is your put few stacks of your E on enemy adc and then put 1 stack on dying creep so when you execute creep you get reset on E and you deny enemy CS with poke. As long as your support triggers W with AA you should win any early trade. Mid game once you get your hurricane if you are not having most farm in the game, you are doing something wrong. Dragon/Baron steal should be impossible thanks to your E. Late game pretty standard for adc, stay behind front lines and stack them up, as long as you don't get one shotted you should be able to kite any assassin.
And for those with duo partners, Ballista is bloody fun! My build goes Botrk/BT depending if you are losing or dominating early, and AS boots with furor upgrade asap , hurricane for double stacks and sweet AS. afterwards you should get your second life steal item(If you bought Botrk now you buy BT) and last whisper. Last item is optional depending on situation i usually get QSS because CC is what gets you.
I really hope i helped, if you have any questions feel free to ask and wish you luck kiting enemies to death!