I had never thought about that Dean, but it does make a lot of sense; basically you can gain 2 vertical pixels (⌂Y) over the course of a "broad jump"so you'd want to, ideally, get one of the pixels at the beginning of the jump (allowing a later departure) and the other at the end of the jump (around the left edge of the last trailing barrel). I would say that I have NOT been actively jumping from spots that are "conducive" to this effect, perhaps even larger jumps are possible. So, essentially any up-hill running jump is going to gain a minimum of 1 vertical pixel, I'd imagine (no knowledge on debug) that statistically speaking, a 2 pixel jump is less common.
Dave, I remembered reading that barrel speeds were consistent, but I had often wondered if the slopes of the girders changed, thanks for that clarification.
I am adding another 2 videos; large jump(s) 4 and large jump 5. I think that large jump 5 may be the largest yet, although there were fewer barrels, it looks like jump 5 only had a ⌂Y + 1, implying there is potentially a bit more room.
Large Jump(s) 4
http://www.twitch.tv/f_symbols/c/3522830Large Jump 5
http://www.twitch.tv/f_symbols/c/3522859EDIT: I just noticed that at the end of "large jump 5" (last jump) there is a good example of a ⌂Y+2. Also, I've added a photo from just prior to takeoff.