I agree with Miss re the time factor on puzzle caches, the 30 minutes is in the guidelines but only applies to traditional caches and similar types. I also very much agree with StationMaster on puzzle caches. My statistics on the 2011 caches show how unpopular they are, especially the very difficult ones. They appeal to a very small audience which is a shame considering the effort that has been put into some of them.
In particular, muddypuddles Great Scientist series were, in my opinion , far too difficult and resulted in very few finds. I worked out 3 of them but really can’t be bothered with the rest. Which is a shame as I am sure the caches are very worthwhile finding especially if they are as good as Hobo suggests. I did think I might try to work out some of them in the dark winter nights, but devoted my time to generating this web site instead! I much prefer his Dartmoor Forest series, which is where I was both Tuesday and Thursday (not that I’ve seen StationMaster’s name on any of the logs!)