Call in back up...

I have been TTC since Feb.27 ( the day my Mirena was removed) AF was MIA for the whole 8 yrs I had the IUD. AF arrived in April twice...lol. I have been relying on Glow to tell me my ovulation dates. I started Vitex 3 weeks ago and SO started Maca root the same time. I am wanting to start using OPKs... what brand do recommend and find most accurate??? Please help!!!! Thanks in advance!!!