i also prefer single cell lights as user lights. (mismatching different voltage cells and only needing to carry one spare battery to make it work again instead of two)
for longer actual use i do prefer longer frame lights too. longer use as in more than couple minutes at a time.. bigger lights that "fill the hand" are convenient to use when task takse more like 5-30minutes. any longer than that.. then i suggest headlamp
pd30 sounds right length for lengthy constant use.. (i use Lmini2 as that.. with 18650 battery.. other choice for similar size is jetbeam pro3 st. the 18650 has more runtime than two cr123s and its rechargable.. )
this size already asks for big pockets or belt holster in my mind. smaller lights you may still carry conviniently in your pocket.
1cr123 lights are too small to my liking too. thats why my most edc lights are AA lights.. nitecore d10, 47s quark aa, jetbeam pro1, etc. and they all are also compatible with Li-ion rechargable 3.6v battery (14500) too. if i carry two AA sized lights on me. other has Nimh and other has li.ion in it. and i can still mix them up if needed. i do like the option of using primaries and rechargables in same light. and AA battery lights do work sufficiently with basic alkalines bought from closest store if neccessary. (or harvested from closest tv remote as it happened with my itp eos couple days ago)
and i do not like to use primary cells as my user lights. i keep them as sparebatteries but actually i use rechargable versions in every light i truly use.