Q1 - One of the DIY articles for powered risers - http://blog.zorinaq.com/?e=44 - has the power wires from the riser cable disconnected from the mobo side and directly connected to a power connector, what I'm wondering is if there is any problems with doing this for all cards so the mobo only handles communication.

Q2 - The PCIe slot has to supply power to more than just the memory because there are cards that don't require supplemental power connections.  I'm trying to figure out if all power connections are drawn from at the same time or if they might kick on as needed ie from 0-75 watts of consumption, power only comes through the PCIe slot, 75-150 comes from supplemental 6 pin connector #1 and 150+ comes from supplemental 6 pin connector #2.  I would assume that power draw comes from all 3 and not in stages but some clarification from someone who knows would be better than my assumptions.  If all else fails, when I get a GPU I can just test it.