Building myself a grow light looking for some guidance

im planning to build myself myself a LED Grow Light for my herbs
currently im growing rosemary and basil


my want.
i want a passive design because its more energy efficient and less points of failure.


here's my current parts
the heatsink http://www.ebay.com/itm/251860684868?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
5 "full spectrum" 1 watt LEDs (with board) http://www.ebay.com/itm/12229020160...49&var=422777564891&ssPageName=STRK:MEBIDX:IT
Arctic Silver Alumina Adhesive Thermal Epoxy


i need to purchase the power hardware (PSU and driver, and resister (if needed))


i have all needed tools.


i dont need dimmers because i am using a timer.


i was using this page for my calculations
http://ledcalc.com/


my calculations show i need one of the following for 5 leds
for a 12 volt supply i need a 726.3 ma and 2 resisters a 1w 6.8 ohm and a 2w 15 ohm resister
for a 19 volt supply i need a 366.5 ma and a 1w 8.2 ohm resister
for a 20 volt supply i need a 333.3ma and a 1w 12 ohm resister
for a 24 volt supply i need a 363.6 ma and a 1w 22 ohm resister


now my questions.
1) how many of leds could this heatsink safely use if i do a passive cooling setup? how about a active cooling setup?
2) if i put a driver in this circuit what changes?
3) what driver should i use? im new to LED drivers, and am completely lost in the sea of information.
i would like to use a 19 or 20 volt supply but am willing to use a 24 volt supply if i have to.
my reason for wanting a 19 V supply is i already own it and its the second most efficient supply in my list
a 20 V supply is the most efficient of the voltages i inputted into the calc
a 24 V supply because they are readily available
4) i am seeing some specks on the backs of the LED boards, should i worry about those?


im most concerned about one in the first picture
left column, third row
its deep enough that my fingernail catches it.

thanks in advance.