Well, I wont quote any specific reply here but just give my 2 cents on the issue and also my personal experience, as well as past and present use of BCAA's.

First and foremost. 2:1:1 is standard in most supplements you purchase. I have always found this works well and never seen a reason to change it.

Definitely you would be wise to use them pre workout with some carbs and during workout (possibly with carbs as well). What this is going to do is reduce central nervous system fatigue and delay onset of lactic acid.

There are two mechanisms by which this works, and why this is beneficial. When your body needs ATP to perform muscular contraction it can break down glycogen via glycolysis or catabolize BCAA's for gluconeogenesis.

When carbohydrate stores are low, conversion of ADP to ATP slows down, creating a buildup of ADP and thus muscle fatigue.

Now, since we want to buffer lactic acid and spare glycogen so we are not tapping into skeletal muscle for energy, we know BCAA's can be used to make ATP. The interesting thing is that BCAA's and tryptophan (another amino acid) convert for the same protein receptor. When our BCAA intake is adequate tryptophan levels are kept in check. Now when you are low on BCAA's or dont consume any than any reserve we have is depleted quickly, thus serum levels are low and tryptophan levels are higher than BCAA's, skewing the balance and allowing tryptophan to bind to the protein receptor carrier, once it passes the blood brain barrier and stimulates in increase in 5-HT (serotonin) that is produced. If enough is converted due to low BCAA levels mental and physical fatigue will follow.

Taking BCAA's are going to also help maintain BG levels, this is going to help with a more stable and controlled level of energy throughout the day when taken between meals. Free form amino's HAVE to be consumed on an empty stomach, so why not consume them between meals? Increase protein synthesis, stabalize BG values and increase anabolism. That is the ENTIRE point of bodybuilding anyhow isnt it...to be as anabolic as possible 24/7. Any edge you can get is something worth considering and from personal experience BCAA's are going to give you the best muscle building potential of any supplement out there. Sure there are others to speak of and we all have our preferences, but the pure mechanism by which BCAA's act in the body make them beneficial for any athlete at any stage of competition (cutting/bulking or in between) and have no ill effects I have ever come across and I consume usuall 50g daily.

Best way to consume imo:

Upon rising
Pre training
Intra training
Post training
In between meals (if you want)