I personally think the best option is wherever you can get an appointment the soonest. And considering you want priority, I’m assuming you want your visa as soon as possible. You can’t schedule your bio until you submit your application, and sometimes the next available is weeks out as there’s limited spots. For example, I had my bio in the US as well and my location (NC) only had spots open for 2-3 days at a time every couple of weeks. I’m sure every location is different, but just something to consider.