Linda and Willy are both on port gybe, approaching the leeward mark
on a run. Willy is clear ahead before reaching the 2-length zone, and
stays clear ahead (but just barely) as they reach the mark. Willy
hardens up to close-hauled on port, and Linda does the same, rounding
wide and going faster than Willy, ending up overlapped to leeward.

18.2(c) says:

If a boat was clear ahead at the time she reached the
two-length zone, the boat clear astern shall thereafter keep
clear. If the boat clear astern becomes overlapped outside the
other boat, she shall also give the inside boat room.

and 15 says:

When a boat acquires right of way, she shall initially give the
other boat room to keep clear

Given those two things, how much room does Linda have to give, and for
how long? Can Willy foot off, or is he obligated to assume a proper
course to the next mark (i.e. close hauled)? If Linda can point
higher than Willy (for whatever reason), when can she begin to
exercise her rights to come up to her proper course and force Willy to
tack away?