It totally depends on each unit. I rushed the Idaho ANG and they said that it takes at least 2 years (2 sets) of interviews and rushing before you become a serious candidate for them. That being said it totally depends on your qualifications and how the unit feels about you. Sometimes you just put out the right vibe and they like you so much that they pick you up on your first board. 

The key is rushing. Get to know them. If there are opportunities for you to rush outside of official interview dates, DO IT! They will see that you are serious, and if you present yourself well you will be one of their number one picks simply because you have been rushing the unit for 6 months straight. 

I have met some people that have been interviewing at the same unit for 4 years and still haven’t been selected, and I know that some people get lucky and get picked up on their first try. 

Good luck! Go out there and make friends, and show them you’re serious!