I mixed 50L Happy Frog with 48L of FFOF soil, it works out to 5 5gal pots.
If the OF has nutrients in it and does not need nutrients added to it for a few weeks do I start my FF nutrients from the week I am in at that time to the feeding schedule for that week?
Thank You in advance for your time.
The norm is usually 4-6 weeks no nutes, from what I understand. Read your plants. They will tell you when they are hungry. 
Just monitor your runoff ppm of the soil. Once the ppms drop below 1000ppm you can pick up in the feeding schedule with wherever your at in your grow.
Between 4 to 6 weeks is standard for brand new FFOF soil. Happy Frog I have never used. 