You are correct, once on Natural Instinct the Boarboys will only move 20cms. You can get them to at least half way under orders so the 20cms is usually enough to get them into contact with someone though
Yeah, I never much understood why GW limited the Pulsas to 30 degrees. Having said that, if you fan out a battery of 3 Pulsas you can cover most of the board in at least one arc. They are another of those units that can turn a battle, or completely fizzle. Even though I tend toward the serious, I usually try and fit a battery in. If nothing else they usually force an opponent to space his forces out a bit more than normal, and this often benefits the KoS. Just leave that big pie plate template in plain view
Pulsas join a group of units I will almost always take when playing Orks. They join the Freebooterz in a Skullhammer for snatching that objective off by itself, a KoS totally maxed out with 5 extra detachments each with 5 things (Bikes, Gobsmashas, Warbuggies, Wartraks), A (often mechanised) Bad Moonz Clan to move forward and sit on objectives, blasting gits with their superior firepower, plus a cheap Evil Sunz Clan to guard the backfield with a Soopa Gun protected a Dragsta, and also providing orders and psychic power for the Weirdboy tower the Bad Moonz left behind, also conveniently under cover of the Dragsta. I quite like adding the Renegade Mekboys to the KoS if points permit, though I only take Lifta-Droppers, Kustom Cannon in small numbers and a Dragsta. Add a Gargant of choice + some flavour and you are ready to stomp.