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I had a bit of an email chat with Dan Perry on this a few years ago. Based on what I learnt from him and my personal experience of hickory and bamboo backed Ipe ELBs this is my take on the subject.
The effect of PR needs a fairly thick belly glued under tension to a backing. The effect is not gained by glueing together thin laminations because they each bend and no real tension is built up in the glueing.
There is a practical limit to the amount of sensible reflex glued in. Too much reflex and the bow is too unstable if made too narrow and if made wide enough to be stable and of a sensible draw weight the thickness of the belly stave can be too thin to gain the PR advantage. I think the amount of reflex limb thickness/width ration would differ between woods. A good example of the limits was a hickory backed Ipe narrow ELB I started with around 7 inches of glued in reflex (5 once out of the form) that was pulling 120lb to get the limb tips 3 inches behind the handle! It was desperate to twist itself unstrung. In an effort to get it strung atahigh and stable brace height I used a fastflight strong string. It stretched this, twisteditselfthe wrong way round and broke! It was just too extreme to ever make a usable bow!
To gain maximum performance the belly stave should be pre-tillered so that once glued up the minimum wood is removed to finish the bow. Removing failry small amounts of wood from either the backing (losing reflex and power) or belly (increasing reflex and reducing power) will cut away the wood under PR tension and reduce performance. Side tillering will not have this same effect. The poundage of the bow will be reduced but only small and proportional amounts of the PR advantage will be lost.
On average adding a backing to a belly can be expected to raise the final draw weight by around 10lb. Each inch of reflex in the form (what you put in at the time of glueing not what you end up with once out of the form) can be expected to raise the draw weight by around 10lb. So a belly stave that would make a 60lb self bow can with a backing and 3 inches of PR reflex make a 100lb bow.
Tillering a PR reflexed can be confusing if material is removed from the belly after glue up. Reflex can actually increase quite a bit as wood is removed as the backing now pulls harder against the belly and weght does not drop off the bow or tiller shape change in quite the predictable way a self bow or straight glue up bow will. I have found that shape can keep changing as the tensions alter and that weight can suddenly drop off.
Go careful and you can have a stunning light in the hand high performance bow though.
Mark in England