B'rachot on Tallit Koton and Tallit Gadol

I recently came across this during M"B Yomit

Mar'eh M'komot
SA O"Ch 8:10
M"B 24

The issue:
Making a B'rachah on BOTH Tallit Katan AND Tallit Gadol

1. If one blesses on BOTH, the M"B is concerned re: B'rachah Shei'eino Tz'richah

2. Secondary Concern - that the T"K might not be a 100% Tallit, therefore it is best to make B'rachah on T"G only.

The M"B never addresses the case of wearing ONLY a T"K

Implication:

Sh'ma Mina, that the M"B presumes that one will wear both T"K and T"G! Furthermore, it implies that bachurim wear a T"G - unless every boy marries at age 13.

Shanah Tovah,
Best Wishes for 5773!