And too add to that last idea it would be cheaper / easier, just to add a filter to the output of the adf4350 VCO/PLL, if I was really worry about the 2nd and 3th order harmonics. Witch in a lot of casts, would not be a problem since the 2nd order harmonic would not be passed by the antenna, and the 3th order harmonic would be so low in power, that it would not really be much of a problem.
At most my final out power is going to be around 350mW.