Additionally, if you do not meet the RS gold requirements of the quest for the helms, GET THEM. If you're planning on doing any slaying whatsoever you should take on this Smoking Kills quest as soon as you are able. Don't be afraid to try different methods and find out what works for you.
This whole setup will cost you roughly 2-2.5M it is a fantastic overall configuration for slaying. Remember to also use some of that cash to buy super sets (Super Strength/Attack/Defence potions) that you should be using on ALL your slayer tasks.
You may think you're paying an amount of money at first, but it can speed up your work considerably and is well-worth the buy OSRS gold cost, and you'll benefit from your slayer drops / clue scrolls, regardless.