So I streamlined the Tetrinsic concept in an effort to give the TimerSpy the best chance of success. There's still an issue that I've just glossed over this entire time: hand mounting. 

It seems that an ergonomic solution is one where the Tetrinsics are, at most, 90 degrees from the fingers if the hand was flat. I think the minimum bound is somewhere around 30-45 degrees. However, the most ergonomic orientation of the screen is perpendicular to that (so parallel with the side of the hand where the thumb is). The second most ergonomic is on the back side of the Tetrinsics, which seems to be a straightforward location to mount the screen. 

Since both #TaskPercent [gd0140] and #Interval Provisional [gd0097] use colour to convey information quickly, I don't know of any >=600 nits screens (let alone a 3"-ish one), I'm trying to keep things low-power and the backside of Tetrinsic needs to be smooth (so I can't mount a frontlight overtop), it seems that I've got a simple yet inescapable choice and I'd have to use the rather expensive 2.7" reflective colour LCD.

Back to the mounting situation, I can only imagine a solution that is similar to "gest":

The issue I've been having for the past 5 days is that:

• I need to fit in a battery and speaker somewhere. 
  • It's likely going to be a 18650 but I'm looking more towards a 5Ah 26650. 
  • It doesn't seem like there's any good off-the-shelf phone speakers that... probably sound better than generic phone speakers. I'm considering going with a smaller battery just so that I can have a speaker with more low-frequency response to improve my Interval Provisional experience (I want to use low-frequency sound effects for a calm/focused feel).
• I'm trying to keep the width of the TimerSpy under the width of the hand so that I can still rest [the side opposite the side of my hand with the thumb] on objects. However, for a gest-like mount, it would need to be wider than the hand so that it could wrap around it.
• The fingers will exert a significant moment about the palm of my hand. This means that magnetic solutions are unlikely to work.

The Tactigon Skin is a potential mounting method whereby I can put the battery and/or speaker on the rear side:I'm considering using the 80x15mm samsung tv speaker I found for TyMist on the back and a 26650 under the Finger2-4 Tetrinsics:

At the end of the day, the human->computer and computer->human pipeline/interface is the most important pipeline/interface of most of my projects. This specific project is essentially the equivalent of PC RAM for people (where short term memory is cache and long term might as well be eMMC) so I've got to really make sure it's done well and that means that audio quality should be at a similar calibre of consideration as Tetrinsic, not a painful afterthought like in so many portable devices of the last decade. Turns out just under 80% of survey respondents say that good phone speakers are important. A solution might have an Alienware / OneNetbook GX1 look to it, where that back grill is the speaker:

The resultant TimerSpy might not be able to slide into a pocket but it'll still look aerodynamic.