So I am doing this project and require quite a bit of reach. I would be using F12 and require a lens to provide decent IQ. My budget is under 10K.

I have narrowed down to following lenses:-

Sigma Lens 50-500mm f/4-6.3 APO EX DG HSM + 2xTC
Sigma APO 150-500mm f5-6.3 DG OS HSM + 2xTC

How will these fair compared to Nikon 300mm f2.8 ???

Also is there any other way to get similar reach but with better IQ.

Thanks