Neville — see HaYom Yom for 19 Av (Chabad.org) for a summary of the 4 types.
cherrybim — Rav Moshe Feinstein, zt”l wore R”T tefillin later in life.
MDG — the size of S”R is an inyan of Kabbala; the small ones (Rash”i and R”T) together add up to 43 (in size) when worn.