Upon further review, it seems that I mixed the 300mm f/4 with the f/2.8 in terms of price, as I did not realize how relatively affordable the f/4 is until I looked at it on B&H's site. This is well within my reach, once I decide upon what to sell, of course.
Question: What do you 'lose' if using a 1.7TC over the 1.4? Looking over my images from when I shot minor league baseball, I realized that I actually was using the 1.7 with the 70-200, as some of my images were '340mm'. At any rate, both of those were sold a while back when I decided to not continue my affiliation with the team.
"Every moment in life is unique and will never be repeated. These are the moments that present the greatest opportunity for a photographer..."