Although it is cool to DIY, and I do admire your handywork, I personally can't trust myself to DIY cooling for my favorite ram, which is Crucial Ballistix 1066, which I regularly overclock to 1200. It got so hot that I burnt my finger on it with the factory heatsinks. I measured with my infrared thermometer and it read 138F. I ended up resorting to using
Thermaltake CL-R0026 heatpipes . They lowered the temps down to 102F, which I am quite happy with, considering I am overclocking so much.
As far as your pipes are concerned, I do see 1 issue. Your pipes are not as long as the heatsinks. This leaves no area for a cooling area, where the acetone can cool down again. If it can't cool, then you aren't having as efficient of evaporation/condensation cycle. Thus, you aren't releasing the heat from the heat pipes as much as you could be.
Much like the Thermaltake solution, I would recommend using longer pipes that have an area that can be air cooled without contacting the heatsink itself.
Another issue is the pressure of the acetone. If you lower the pressure in the pipe, then the acetone should evaporate at lower temps, thus increasing performance. However, that requires vacuum and other equipment that I don't have, and is the primary reason why I can't DIY mine.
edit:typo in url...