With a Harries grip, you pretty much must have a forward-clicky tailcap switch, either 1-mode or separate side-switch to set modes while the tailcap is simply on/off.
Best bet, and my former EDC light, would be a Nitefox UT20, described above to a tee.
You want a simple tail-clicky for simple on/off to avoid confusion. The last thing you want is to go switching modes to moonlight(!!) or something when you just want the last mode used.
You also want a forward-clicky (momentary-on, vs momentary-off) so you can do a quick flash’n’dash, without incessantly clicking-on and clicking-off, potentially giving away your position.
And while it’s a bit unique to the UT20, it has “EDC mode” and “tactical mode”. I hate blinkies so would (and did) avoid “tactical mode”, but if that’s the better choice for you, then you at least have that choice.
That said, the Nitecore P30 has a forward-clicky tailswitch, throws like Hell in a nice tight beam, but has a big head/reflector to match. I didn’t review my P30s, but you can goggle around for more info. Makes a great “wotnahell’s making that noise out back??” light for the nightstand.
Better yet, just get both.