As of November, George Harrison is the first ex-Beatle to conduct a formal American tour. Harrison started in the northwest and will finally wind up On the other side of the continent at Christmas time for three shows at Madison Square Garden and two shows at the Nassau Colisseum — an optimistic prediction of audience turn-out for an artist whose last album sold disappointingly and who has been largely out of the public eye. Robert Stigwood, Eric Clapton’s manager, felt that Eric’s protracted layaway had only enhanced his appeal, and the enormous success of his comeback tour proves Stigwood correct. Perhaps the same syndrome will benefit Harrison; undoubtedly, Harrison and his business associates are counting on it.