My problem with the video Camp Freddie posted is that the pilot didn't even pretend to use a checklist, and apparently started the engine with the landing light on. His "flow check" missed it entirely, it seems. And that's what happens when you rely on memorized flow checks.
When I was at PHI, I routinely did five starts per day, sometimes more. Since I flew 7500 hours with that company alone (combination of 206 and BO105). I figure I've done well north of 50,000 starts of RR/Allison C20B engines. Yup, whip 'em out, boys! Let's measure ;-)
In the C20B it absolutely doesn't matter how far you open the throttle at lightoff. "Cracked" is the same as "Full." Get it back to the idle stop before 58%. The engine will be "self-sustaining" above 45% or so if it's accelerating smartly. Most pilots are OCD about holding the starter down until 58%. You don't have to; anywhere above 50% is fine and won't hurt it.
Before PHI, in the 206 I always used the right-hand index/middle finger for the idle release and starter, with my left hand dedicated solely to the throttle. Then I went to PHI where they put the starter button on the damn cyclic: Left-hand and thumb for throttle and idle release! After PHI, back again to the old way, which works for me.
There is no single "right" way to start a 206 when it comes to which fingers/hands to use. Just don't screw it up!
In all of my flying, I've never seen a TOT take off so fast that it couldn't be caught. Expect the overtemp, and don't be surprised when it happens. Just be sure to keep both buttons pressed.
Me, I check for oil pressure AND blade turning before lighting it off. That eliminates the often-overlooked requirement to ensure that the MR is turning by 25%.
Now I fly helicopters with piston radial engines, and I think back fondly on how easy turbines were to start by comparison. Aye carumba!