I must admit I'm a bit ambivalent about the whole lower limb stiff thing. It's not so critical on ELBs.
With the arrow pass 1" above centre my bows end up with a shorter lower limb. (grip approx 4", so ball of the thumb is supporting the bow about centre)
I tend to just make sure I tiller the bow supported (loosely, not clamped) and drawn as it will be in the hand and just get it looking even, (with maybe the lower limb a tad stiffer if there is any asymmetry).
Pulling it like that on the tiller, it starts off canted over towards the upper limb (because the draw is bound to be above the hand position) and it pulls back straighter as it is drawn.
You can see what I mean in the video in this blog entry, it starts with the bow tilted down on the right (top limb).
http://bowyersdiary.blogspot.co.uk/2012/11/it-lives.htmlI've only had one bow really shift on me (Ash primitive), but I make sure I give my bows plenty of exercise these days.
My last ELB ended up getting turned round, as supporting it dead centre and pulling it 1" above centre looked very different to how it looked with it turned round (effectively a 2" difference in where the string is pulled made a visible difference to the tiller).
Have a look at the pics here on my blog.
http://bowyersdiary.blogspot.co.uk/2012/11/caramel-and-cream.htmlI invited comments in that entry, but got none!
Del
(Sorry this post is so long
, but it's a good topic)