http://www.bwrs.org.au/sites/default/files/PulleyReport/PulleyReport-w.html
Unsurprising results, it pays to carry the heavier pulley gear, I'd be interested in a study comparing the most common pulleys used here in the context of crevasse rescue systems.
A nice summary of the data is below, I've counted Carabiner as 0 as you've got some in your system no matter what, pulling out the efficiency % numbers, ignoring double ended and specialty systems.
| kg | 3 to 1 | 2 to 1 | 5 to 1 | 1 to 1 | |
| Carabiner | 0 | 75.6 | 75.3 | 53.5 | |
| PetzlUL | 0.01 | 83.9 | 73.2 | ||
| RSBB | 0.085 | 81.5 | |||
| RM15ARS | 0.132 | 79.3 | 90.1 | 61.3 | 86.5 |
| OB11S | 0.14 | 81.1 | 91.1 | 68.3 | 87.1 |
| OB15S | 0.26 | 85.5 | 93.2 | 73.2 | 92.2 |
| RP102S | 0.29 | 86 | 93.2 | 92.9 |
In the context of, say, the pulleys sold at MEC, the 40g Stubai with a nylon wheel is little better than the 10g Ultralegere that is in the study in terms of the wheel and what it is spinning against. However, it's not clear to me how much better the SMC Prussik Minding Pulley might be at 105g, it has the guards to prevent your prussik from being eaten by the pulley, but the primary weight gain is in having a sealed sheave that has ball bearings inside. And stepping up again to a beefier Rescue Pulley at 185g, how much better is that? Not being familiar with most of the tested devices, it's hard to translate to the devices I've played with. Food for thought though in the weight weenie / safety balance in picking your glacier system.
I dont see my favourite pulley/caribiner
http://www.mec.ca/product/5015-812/dmm-revolver-screwgate-locking-biner/?h=10+50019&f=10+50262