Descent soldering skills as in you can solder an Atiny13A chip to a 17mm pcb? A satisfying driver to build would be a 17mm FET+ 7135 driver from mtnelectronics. Let me find the parts kit…
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Kit
PCB
I was looking for the FET driver without the 7135 chip but can’t seem to be able to find the PCB. grrr. (The mtn max driver is pretty cool but is MORE advanced. ) The driver when complete can be used to power a single XML2, XPL or a tripple XPL, XPG2 or tripple Nichia 219B/C depending on which host you choose. (Convoy S2 can be used for the tripple with an additional spacer)
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WRT programming, others who can, will jump in but, you can order a blank atiny from RMM if you want and program it yourself with firmware available here or something you come up with 
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Programming: How To Build a Flashlight With Perfect Modes (picture heavy)
STAR Firmware by JonnyC - Source Code and Explanation