best tme of year to take "Best of Spain in 14 Days Tour"

John, I took that tour in April 2016, and both the tour and the timing/weather were terrific, at least for that year. I spent a few extra days in Barcelona before the tour, and then a few in Andalusia at the end. During my time in Andalusia I caught both the Patios (flowers) festival in Córdoba, and the Cavallos (horses) frestival in Jerez de la Frontera. All good!

Well July and August will be roasting hot , we've been to Spain twice in summer and it does make sightseeing hard when heat is oppressive

I'd aim for the middle 2 weeks of May.

In my opinion, based on about ten trips in this time frame, the ideal time of year to travel in Spain is late September through the end of October. If your itinerary includes beach time, of course, this will need to be modified.

Best of, is rather generic, as is special holidays. The weather in Spain is very diverse; cooler in the north and hot in the south and Extremadura. Each region has its own special holidays. On my last trip to southeast Spain in mid-September 2014, there was a heat wave and it was in the mid-90s most days. We generally try to visit in May or Sept/October. June through August are out; too hot and too many tourists.