WHAT IS TH EBEST ANGLE FOR THE SWUEEGEE BLADE TO BE ANGLED AT? WE ARE USING 45 DEGREE ON OUR POLYEURETHANE BLADES, AND I BELIVE WE HAVE TH EOPTION OF EITHER 45 OR 60 DEGREES ON OUR METAL BLADES. WHICH OF THE TWO IS BETTER, OR SHOUL WE BE USING ANOTHER ANGLE?