In a fight between two California attorneys and a Chicago law firm about the validity of an agreement to split fees from air crash cases, U.S. District Judge Matthew F. Kennelly had to decide whether Illinois Rule of Professional Conduct 1.5 permitted a nearly two-year delay between the date of the deal and the date the clients signed contracts that complied with Rule 1.5’s informed-consent requirements.Mirroring the Illinois rule, the American Bar Association’s Model Rule 1.5 doesn’t have an express deadline for getting …