easternUSA.jpg

Signal/Noise graph produced by ACE-HF
This shows that to work the eastern US-based stations from within the UK, 20m (14 MHz)
is probably your best bet from around 1100UTC, dipping at about 1230UTC
and then stronger in the afternoon and early evening.
40m (7 MHz) is a possibility after dark on Saturday evening and
the early hours of Saturday morning.
Note the possible 10MHz openings - I have never heard IMD
stations on 30m myself.