A lot will depend on the contrast of the scenes you photograph. In general, high contrast scene= low film speed, low contrast scene= high film speed. Another important consideration is printing process. If you plan to print on Azo, it's higher DR requirements and associated extended film development effectively raises film speed. Developer and method of development also play an important part. Some developers won't deliver full emulsion speed, while others will. Assuming your developer does, and you overexpose by 1/2 stop, that's no disaster. If your developer doesn't then you might be underexposing by up to 1/2 stop, which isn't a disaster either. Good luck.