For length, yes. However, F is narrower than P2 and fits differently around the instep.For many, this is a non-issue. For me, it means doing without F or (per recent correspondence with Vass), moving up one width.
There are many beautiful cottons out there, not so many cotton/linens. The sky blues are safer patterns, but I'm willing to take a look at others.One thing to consider is that there are hardly any good yellows anywhere. Bonfanti's current books have two-- but another variation or so would be welcome.