As a 1700 myself, I use the bishops opening and caro Kann
best opening for 1700?
Try "several centuries".
The first chess problems (tactics exercises) that have modern solutions were published c. 840 AD.
The first chess book using recognizably modern rules (castling, en passent, etc) was published in the 1470s.
Now that King's Gambit has carried him to 1800, he can use it to get to 1900