Which B737? ON NG's F10 is same speed as F5 but more drag, so doesn't seem a good idea. On the classic with fixed speed schedules for flaps, F10 will give you a reduced IAS and at max wt. bring you within Cat C circling minima. At high wt's. F5 might take you into Cat D and perhaps higher minima. You'll need to check the speeds; I don't have them to hand.