Harington's Epigram 81 on "Don Pedro" seems very likely to have been another lampoon of "Gullio." "Don Pedro" is (1) a patron of poets who pays low wages to his hirelings; (2) a well known sonnet writer who didn't actually write the poems credited to him; and (3) a man implied to have recently married the former widow "Lesbia," a one-time beauty gone to seed.
Harington's Epigram 81: "Of Don Pedro and his Poetry"
Sir, I shall tell you news, except you know it
Our noble friend Don Pedro is a poet.
His verses all abroad are read and shown
And he himself doth swear they are his own
His own? Tis true for he for them hath paid
Two crowns a sonnet as I heard it said
So Ellen hath fair teeth, that in her purse
She keeps all night, and she sleeps near the worse
So widow Lesbia with her painted hide
Seemed for the time, to make a handsome bride
If Pedro be for this a poet called
So you may call one hairy that is bald.
Harington's Epigram 82 provides context for Ingenioso's claim to have written poetry for Gullio in exchange for money. Although nearly all the Elizabethan poets lived in poverty, this epigram makes it clear that on occasion they were paid for their verses in exchange for giving up their authorship rights. Epigram 82 claims (falsely) that poor poets need no longer worry about having a pension, because they can sell their verses to richer men who seek to add poetry-writing to their accomplishments.
Epigram 82: "A comfort for poor poets"
Henceforth for pensions poets need not care
Who call you beggars you may call them liars
Verses are grown such merchantable ware,
That now for Sonnets, sellers are, and buyers.