Any good archer should be used to occasions that they face monsters that can 2hko them. It's part of being that squishy archer. I reach almost 8k HP with everything I have (excluding my Decent Hyper Body) and I still sometimes worry when I fight certain enemies or bosses. It's okay to get worried but you picked the class so time to face the consequences. We're archers. We attack from a distance. We weren't made to be right up in the enemy's face and constantly get hit by the physical and magical hits. We take the long range ones that don't hit as often, but even then we need to be careful. It's part of the archer.
Times have changed. HP washing is no longer necessary. Your HP can and will be sufficient without wasting AP and I see it as if the monster can't 1hko you then you are perfectly fine. You just have to be careful. My base HP at level 166 with the boosts from Marksmanship and the 200 HP I get from the Willpower trait is at 5423 HP. That's a nice sum I think and it is very helpful when I equip the %HP equips. The best equips for an archer are ones that boost HP to add for a less squishy attacker and ones that boost stats at the same time. This puts archers at a difficult point since unlike warriors, they have to worry more about survival. They can't just go grabbing tons and tons of damage items and not pay attention to HP because they won't survive very long in bosses like Pink Bean or Cygnus. BUT just because we have to worry about that, it doesn't mean we need to waste ability points or scroll slots. Instead you focus on the base stats of items. Chaos Zakum Helmet and the Chaos Horntail Pendant are great items to look into like you said, but are also very expensive. A cheaper version of these are the Red Rex Earrings. These earrings, like the Chaos items, also give a nice 10% HP boost. The only downfall is the durability. The durability is a lot worse for archers since normally the durability goes down per skill usage, but in Hurricane's case it goes down for every arrow. Needless to say, Hurricane shoots a lot of arrows. Still a pair of Red Rex earrings can last me about 70 minutes of continuous Hurricane spamming, which is still a good time in a lot of places. It is nice though to have a magic door available to repair if you are training at Lionheart Castle. The Chaos Zakum Helmet shouldn't be too hard to get, but the Chaos Horntail Pendant is another story. It's pretty expensive so you probably will have to settle with the Mark of Naricain. If you can get a regular Horntail Pendant with a good potential that increases your range more than the Mark, get it if you have enough HP to survive without the Mark.
My current base HP
My current equipped HP
My current equipped HP with decent HB
Now I admit I did HP wash a few levels before the Big Bang, but that was a different story back then. And also, Rasudoken is right, the formula for HP increase per levels have changed and have gone up. Although it may not seem like much, it does make a difference for new archers. No new archer needs to go through HP washing. It's a waste of points. And if you can help it, try not to scroll for HP. There are many ways to get HP without wasting slots. The several common rings out there are great sources and if you can get the money for it, Decent Hyper Body pants are a great investment.
Also if you think that buying scrolls for defense is a good idea, then you are wrong. Very very very wrong. Even with the new increases in scrolls, you are still wrong. The only way defense can make a difference is if you have several thousand of it. The only real character that can make use of a huge amount of defense is the Paladin because they have Shield Mastery. They can have about 4-5x the amount of Defense that an ordinary archer has without needing scrolls at all. In the end for archers, it's how much HP that matters.
With that said I would like to repeat this once more, do not waste your AP on HP and please if you can help it, do not waste your equipment slots either.