Re: Target size height for mildot ranging (deer and coyote)?
I like to play around with reticle rangefinding myself, and have had more than a reasonable degree of luck ranging antelope to about 400-500 yds.
I was actually successful to 725 yds. once with a buck using a plex-style reticle--BUT that was too much luck to think it could be repeated. I haven't done it since.
I measured 2 "avg." does once at exactly 14" laying on the ground back to brisket, and A buddy and i have both come up with 11" b-b on winter coyotes (5-6" vital zone).
I used a point blank range rangefinding system this last year on a doe antelope with the Varmint Hunter reticle and it also worked. I have done this once before on a coyote with success.
IMO, the PBR reticle-rangefinding system is the most useful system.