Which preposition to use with proficients

in Occurrences 116%

You are grown a notable Proficient in LoveAnd you are resolv'd (if he please) to marry him? Cel.

at Occurrences 8%

Vicars and I were in the habit, since the hot weather began, of making ices every afternoon, and had become, from long practice, quite proficient at the work.

as Occurrences 2%

True, some men, though inexpert as writers, have made themselves proficient as speakers; or though shambling and ineffective as speakers, have made themselves proficient as writers.

for Occurrences 1%

Edward VI.; with the natural feeling of a boy fond of knowledge, and himself a proficient for his years, was aware of the evil, and projected the remedy.

on Occurrences 1%

With a pastor who had loved music from childhood, who taught it in his early manhood, who was himself proficient on several instruments, music naturally assumed an important place in Temple life and work.

than Occurrences 1%

After the departure of the countess, Dick the Scholar took Harry Esmond under his special protection, and would talk to him both of French and Latin, in which tongues the lad found that he was even more proficient than Scholar Dick.

Which preposition to use with  proficients