I bid LC and have in layers 1-3 must off days starting with Fri-Sat-Sun then layer two is Fri prefer off Sat-Sun must off etc.

Layer four I start just doing prefers. I must be doing something right because somehow I get Fri-Sat-Sun must off awarded in layer one even over the summer which surprised me. I guess guys don't like weekends off.

You're senior enough to not have coverage days. Approx 70% (base/seat) looks like the sweet spot to have zero to maybe 1 or 2 coverage days on LCR. I'm guessing you're at 50% which puts you well above it. You can see the coverage requirements for every pilot on the PBS award reports (the PDF document). Yeah, I've geeked out a bit and track this stuff with a spread sheet. Let's me accurately predict where I sit. I pay my 11 year old to do the data entry from the PBS report to the spreadsheet:cool:

Added: by the way, if you start doing ALL prefer off in layer 4 you will solve in layer 4 so you're wasting layers 5-7.