OK, clarification: I hate the idea of stripping down a functioning driver just to get a blank contact board. I like to re-use leftover stuff when possible.
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The capacitor can be smaller if it's placed closer to the attiny, that's what I did on the latest version of the red 'JB' driver. It can go anywhere that's electrically the same as stock, between MCU pin8 and GND (the red Vcc trace).
It can go on the reverse side in parallel with the original, off the bottom of the diode to GND, off the bottom of R1 to GND (I relocated the original cap to this spot, so I can coat the backside with JB Weld and not have any components inaccessible), or straight onto the Vcc pin on the attiny (though, this can block access for the programming clip).
The attiny will drive the 2SK4212 FET directly with no resistors added anywhere - other FETs give different results. The red 'JB' driver works as-is.
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I've used the 095b version of the FW on several lights, and even on a 105C still using the original 7135s (in a little UF-T50; tested, but not assembled yet), and the mode spacing has been good on all of them. The big single FET drivers still look 'right' when used with a single cell & single LED, so it should be good for a East092-style driver as well.
Comparative, not absolute (it's not dark, ambient light not subtracted), ceiling bounce lux numbers for some different lights...
6x XML2, direct drive JB driver, Werner's 095b FW
7.8
17.9
32.3
61.2
101.2
3x XML2, direct drive JB driver, Werner's 095b FW
8.6
18.9
33.0
59.2
94.4
3x XML2, direct drive JB driver, stock 3-level FW
22.3
54.6
84.2
3x XML, stock 3-toroid SRK driver, stock hi-low FW
10.9
53.5