Stick with the low. Perhaps you can pitch the yeast at about 70, wrap a towel around it until it starts fermenting and then remove the towel. With active fermentation it'll keep itself in the 64-66 range. At 75 ambient it'd be more like 80 which is not preferred. Low end of the scale is where I always prefer to be. If a basement & you can keep it off the cold cement floor that'd probably be a plus.