Another note of interest...efficiency. I dug around on HD, Lowe's, Ace, etc. and found that most bulbs found in popular hardware stores were mostly equivalent in lumen outputs given a specified wattage (all bulbs are 2700K models).
~ = approximately
68W ~ 4200L ~ $15 @ HD **61.7 L/W**
42W ~ 2600L ~ $10 @ HD **61.9 L/W**
26W ~ 1700L ~ $2.80 @ Ace when bought as a 10 pack **65.4 L/W**
23W ~ 1600L ~ Don't know, didn't really look since for three more watts you get 100L of additional output. **69.6 L/W**
Which bulb wattage is best? Depends on your grow and your budget. It will cost you more in bulbs to get the same lumen output from 68W as it does from a couple of 26W but the standard wattages increases by ~162% from 26W to 68W. Since it's not an integer multiple of the original wattage 2 26W is not equal to the next larger which is the 42W and so on.
Another thing to consider is the hardware costs required to rig up more lights. The question here is how long do the bulbs have to last with the rest of the chandelier hardware before you reach the break even cost point? You will need to know your cost per kw along with your planned lighting cycle for the entire grow to calculate this but it can be done. The point where the extra cost of the additional sockets and such is made up for by the extra efficiency/output of the lower wattage bulbs versus higher wattage bulbs with less required hardware but reduced lumen output.
2 26W CFL's (52W)= 3400L @ ~$6
or
1 42W CFL = 2600L @ $10
2 42W CFL's (84W) = 5200L @ $20
or
1 68W CFL = 4200L @ $15 (addition of a supplemental 23W or 26W will cost about the same as 2 42W's and increase the lumen output another 600-700L above what the pair of 42W's could do)
3 26W CFL's (78W) = 5100L @ ~$9
or
1 68W CFL = 4200L @ $15
As you can see from the above examples there is a definite advantage in going with multiple smaller wattage bulbs in regards to luminosity. However more bulbs means more mounting hardware.
1 1/4" T @ HD ~ $1.27
1 1/4" Elbow @ HD ~ $1.25
Rubber coated lamp socket @ HD ~ $3.27 (Rubber not required but it's all mine has)
I run 11-12 26W CFL's at the most right now which yielded some very sticky and rock hard buds during my first grow but also would require $30+ just in lamp sockets and another $20+ for the PVC. Now the question for me is, "Should I go with larger wattage bulbs and less hardware costs along with reduced light...or suck it up and stick with a bunch of smaller bulbs?"
When asking yourself that question it really boils down to your pocketbook. We all know that usually the more light the merrier and a mere $50-60 for a better yield may pay for itself in a grow or two...or maybe not. Unfortunately, sort of, I already have the bulbs and am still on a limited budged but the thought of paying $30 just for the sockets is hard to swallow atm lol. Too bad I can't return all the plug-in adaptors and Y-splitters I bought the first time around for a credit...
Anyway, I just wanted to point out an important difference in these bulbs regarding lumens per watt. Although even armed with this knowledge it does not become an easy decision as it boils down to a compromise between cost and yield...but then again we're used to that, right?
One thing I am unsure of is the temperature differences between say two 26W bulbs and a single 42W bulb and so on. If anyone has any first-hand experience especially with temperature differences between them please post them!
I have yet to see PAR on any locally purchased CFL bulbs but that's because regular CFL applications don't usually concern themselves with growing plants. 
