Thanks for the advice, but I don't know if this will help me; I have no issues with the bigram HE. In fact, for some reason H is by far my fastest letter according to keybr. It's words like art, you and key that makes my hands feel uncomfortable.

Maybe your pinkies are a little weak? I feel that 'art' is nice!

Many feel that inward rolls are the best, outward rolls nice, and mixed rolls sometimes problematic. I feel that some rolls may take getting used to and not all rolls are nice rolls, but as a concept they're very effective.

Imagine how you would produce as rapid drumming as you can on a surface. Certainly not using same-finger, that much is a given! Maybe you could get a good one going with alternating hands but if you ask any hand drummer or arabic tambourine player it's finger rolls that really produce the best result. Worth noting. ;-)

I had troubles with "ion" and "star" at first, and in general with the home row words, but now "ion" just coming out automatically without any thinking.

For typing 'war' if it bothers you, I'd consider sliding one key to the left so it's handled by the ring and middle fingers. But I don't, because I don't type that word often enough (and as a result, when I tried it I mistyped it as 'was' way too much).

'You' is quite common, so if you wish you could train yourself to slide and type it centered on the middle finger instead of the ring finger. That seems to work well for me.

Dvorak is usually claimed to have higher alternation, but that has it's own set of other issues, and isn't 50/50 split.

Words like "you" and "war" can be a little tricky to type quickly, but this has more to do with them using ring and pinky in quick succession, rather than rolls per se. I assume you don't have any problem with rolls on stronger fingers, e.g. involving "st" or "en"?

My thought is that it may not be about hand rolls but about pinkies. If your pinkies and ring fingers are weak and/or dependent then 'you' is hell to type on Colemak, and so is 'art', 'war', '-ion' etc. So I reiterate this argument.

Try alternative fingering for the above mentioned trigrams: Slide your hand one key outwards, so that, e.g., 'you' is typed with fingers 3-4-2 instead of 4-5-3. I know that this type of fingering is used a lot by top QWERTY typists! The Colemak FAQ states that these tricks aren't necessary with Colemak but they can still help you even with a better layout! I use alternative fingering for several common n-grams; after a while it becomes second nature.

On the other hand, I do believe and have heard from proficient typists that strong and independent fingers are key to really good typing no matter what. So doing some finger exercises (playing the piano for instance!) will help you too. For the piano there are etudes that really run you through the hoops. Hanon is boring as hell, but Sibelius for instance has the loveliest etudes!

To avoid strain on the weak/dependent fingers, try some of these remedies:
• Wide mod: Relieves pinky strain (by moving keys to the middle, and reducing the distance to Enter/Back)
• Extend: Same (moves navigation and Enter to other fingers, makes Back far more accessible)
• Alternative fingering: Lets stronger fingers take on the most common finger-twisters

Best of luck!