I know ive seen this question more than once here but I cant find it. I have a 066 stihl, alaskan mill with a 32" bar. What is the best combonation of bar/chain to use with this mill. I have a .050 3/8 chain on there now and its about to work me and the poor saw to death.
I don't understand why a 32" bar and 0.050 3/8 should be the cause of "working you and the saw to death". If you are finding milling hard work I think there are other problems with your setup other than the bar and chain
One thing I can see causing a bit of unnecessary effort on your current set up is the gap between the mill and the powerhead. This causes the powerhead to hang out in the breeze which, for a bigger saw like the the 066, will make the mill unbalanced. If possible I would bring the power head as close to the mill as possible. This will also reduce the distance you have to hold your arms apart while using the mill and reduced shoulder and arm pain. Its a lot easier on the operator if they can stand upright when milling but to do that requires something like a remote throttle closer to the mill so the operator does not have to hold their left hand out and down on the throttle. If you look in the Milling stick at post #12 you can see my stance and look at where my arms are - before that I used to get very sore arms and shoulder.
It could be that your mill is too short and you cannot bring the powerhead any closer. If so I would make or buy longer mill rails. Unless you are working in dense bush longer rails also help balance the mill.
With a saw like an 066 I reckon a longer bar (eg 36") and mill rails improve the balance of a mill even when milling quite narrow cants. I have 36, 30 and 25" bars to use with my bigger mill but I have never used them for milling - I mill everything from 40" down to about 20" in diameter with my bigger mill with a 42" bar and 54" rails, 54. For stuff less than 20" in diameter I use a 440 with a 25" bar but even though the 440 is a lighter saw it is not as well balanced as the bigger mill
Chain pitch/gauge is kinda personal - you have to try and see what works best for you.