Howdy discohero, and welcome to CPF,
My 120P just arrived today. I think the main reason anybody would want the T model would be for the protruding tail cap.... but hey, the tail switch on the P model is VERY easy to operate..... not to easy..... just right. I guess if you had gloves, then maybe the T model might be a tad easier, but the button is big enough that even with gloves I think the P model would be easy to work.
And the P is programmable.... I mean hey.... you get to set each light level exactly where YOU want it.... and you can change your mind 5 minutes from now if you want. Not to mention all the other neat things you can do with the programming, like force the light to come on at the last level you used before turning it off if you want.
I got the 120 model because it's the brightest they make. If they offered a 160 or 200 model I would have gotten that. I want the option for the absolute brightest I can get..... then using the 4 adjustable levels I will pick the one I need for the task at hand.
Personally, I set my light to come on at 42 lumens, with my secondary at 5.3 lumens, minimum at .08 lumens and max at 120 lumens. Maybe I'll change my mind tomorrow. It's nice to know I can change it if I want to.
Is the 120 worth the $40 premium over the 85..... hmmmm ..... it is to me, and I guess that's what counts. What's cool, is that if anybody is sitting on the fence about whether to get one of these or not, thinking that $150 is just to much, well..... for just $110 they can get virtually the same light I got, at least for all practical purposes. So, that's my thinking on the matter.
For your situation, rather than buy all three, just get the 120P..... no need to get the 85P if you've already got the 120P. More than likely, you will find that the rear button is fine the way it is on the P model.. and of course you can then program it with any or all of the tactical abilities of the T model if you decide that's what you want. So, the 120 P pretty much gives you best of all 3 models.