I suppose it depends on what sailings you want?
Personally, I want to be there for the whole of race week, so that means being there on the Friday, and coming back after the Senior the following Friday. Years ago, I always booked the sailing for the Sunday after the Senior, as it wasnt uncommon for the race to be on the Saturday due to bad weather.
The sailing I want now is out on the Friday 3,30 am boat, and back on the Late boat the following Friday, both from Liverpool.
One way to avoid some of the strain on the system is to offer an automatic renewal for the following year. I seems obvious, but what do I know.