Join Date: Aug 2017
Location: LAX, BOS, and Seat 1A
Programs: DL Plat, VS Gold, UA Plat, VX Gold (RIP), AS MVP 75K, Starriot Plat, Hertz President's Circle
Posts: 387
Book a roundtrip as soon as F availably opens up on one segment. Call VS Flying Club and book the roundtrip with the first segment in F and the second segment in J or Y. Then, when F availability on the second segment opens up, call VS Flying Club again to amend your booking and change the second segment.
This may incur a small ($50?) award change fee if you don't have status but I believe this is the best way to go about it.