If you solely focus on Swirling Petal then it's easy, you will have a lot of leftover points to put in whatever skill you like, though there are a few things I'd like to point out :
_ Only magic build needs the other 3 charms learned, other than that, only Earth charm is needed and used for KE/Swirling Petal/Kunai Splash.
_Kunai Splash does not suck, whoever told you that on the other hand, sucks. It has the potential to be the best dps skill a Kagerou can get, with appropriate condition, one can get up to 30k per spin, 0,5 cast delay, 11x11 AoE, no godly gears needed, the downside is the cost to maintain it and the need to resupply every few mins if you plan to solo with it.
_Swirling Petal on the other hand, has a huge cast delay, the damage is nice at low level, but get surpassed by Kunai Splash/Explosive Kunai quickly,you'll start to feel the struggle to finish mobs with it once you start facing mobs that have 100k+ HP, which is norm for level 130+ mobs,the good thing is it's pretty cheap to gear up for this build so it's quite popular.
_If you are going to choose KE/Swirling Petal build, then dont put points in Kunai Splash, you will never use it,since most of the time you will alternate between KE and Swirling Petal, plus it needs a highly FS enchanted/Upgraded Grimtooth/QWL + Racial/Size carded Main Gauche combo to dish out good damage.
_Putting points in Killing Strike is a waste, the dmg isn't that good, plus it leaves you at 1 HP which can makes things go wrong pretty quickly if you are not careful, so I suggest not using it. If I were you, I'd put those points in Blaze Shield instead, it's a good skill to keeps the mobs away from you and give you time to finish them.
