Exp. Scrolls

Hello,
With the new update, I've decided to go through with legendary survivor on a couple of characters. I'm doing so with Vaettir farming (HM ofc). I've been testing different types of exp scrolls but never really got how they stack with the HM +50%. So my questions are...
1) What does the exp gain cap at?
2) How do scrolls stack with the HM bonus?
3) What is the scroll(s) that allows you to gain exp. most efficeintly (be at the cap; i.e. which scrolls should I use to vaettir farm in HM - not worried about the cost)
4) Are LB scrolls redundant in HM?

Please don't post the link to wiki as I have read it already, the info isn't really clear and doesn't cover everything.

Thanks!

Scrolls do stack with HM bonus, but if I recall correctly, the 50% wont apply to the triple bonus for LB Scroll. So you gain 350% exp, I think. So yes, use LB scrolls to farm vaettir HM

The Exp bonus caps at 350%, as previously stated

http://wiki.guildwars.com/wiki/Scroll

Should give you all the information you need.

Question 1, 2, & 4 look pretty well answered already.

I just finished this farm for my survivor. No merchants had gold scrolls, so I just used Scroll of Rampager's Insight. I would activate the scroll right before the first large group died, then gather up the other group and repeat. I was getting 600xp per kill or 36k per run. The scrolls were still available at some merchants, but not all. At 250g ea, it was very cheap. Using 2 Rampager's scrolls per Vaettir run should get you survivor in just under 3hrs. About 75 scrolls should do the job, and if you are using a merchant stone to free up inventory - they also have these scrolls if you need to buy more.

Max I got in HM with gold scrolls was about 945 xp/kill, level 30 non-boss kills.
I know this was at the cap because higher scrolls gave same xp.