So, ordered PCB and components. Coils same size 7x6.5mm, 3 values: 5.6, 6.8, 8.2uF and caps 22, 47 and 100uF for experimenting and tuning. 
How are they better than 1616?
The 1616 has a 10 bit adc but it may not matter if you are using an op amp. The little bit I have read about the two series claims very fast adc conversions and a more powerful cpu. Either one would be an improvement on the old 85.
My biggest concern is the attiny could be spending too much time on other tasks and not spending enough time on the boost converter. If this thing works and the switching speeds can be increased it opens the door to higher power versions and maybe buck boost as well.
Just took a closer look…I really like it. 
I wonder what kind of power can it deliver and at what efficiency.
It would be better in 20mm size and 2.5A @12V
I guess efficiency should be about 80-85% and power… maybe 20W?. Ordered few 20mm too.
To be honest I find the efficiency underwhelming…what makes it so much less efficient than say GXB172?
50mOhm series resistor and the rectifier drop, to start. Without a synchronous rectifier, conduction losses really pile up.
Hahahaha, what was that all about
Yes, yes the best is synchronous rectification , but Ill be very happy with “only” 85% eficiency
It's a (modified) commercial jingle for Wrigley's Doublemint gum.
Great job! Looks like getting it down to 17mm is possible.
Awaiting testing data to see how these perform. Very interesting design.
Now components is in 18mm circle all in 1 side, so 20mm possible, but 17mm … 1 side … hmmm ;)) Boost driver without big coil wont work ;))
Am I the only one who gets the Big Ass Spider reference, or am I just late to the game?
Its impressive that you have got it down to 18mm. Is there a reason you dont want to go double side?
This design could easily fit 17mm if you stuck some of the smaller components on the oppisite side. Just leave the center for positive to solder on a copper stud or small spring.
In time, I think Aundril will be adapted to work with boost. There’s a few members working on it.
Which e-switch flashlight using 17mm driver? Another question. Which e-switch drivers diameter most common and popular and desirable?
Most desirable are currently for 14500/AA size if you ask me.
14500/AA…. Its not a driver size
17 mm is considered the most common, across the board. But I've been seeing 20, 21, 22 mm's pretty often lately. Going smaller, AA size, 15 mm would be the next smaller size, I would consider AA size. But of course there are exceptions to every rule or assumption 
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17mm is probably the most common as Tom E said. The easiet way is to make it as small as you feel comfortable working with then just change the pcb size to accomodate different size lights. That way the driver can fit many lights just by changing the pcb size in the design without having to go thru the process of designing a new layout.