Hi!
I haven't looked in detail at the formulas but if DF96 questions them, they might be fishy.
In any case I would consider a 300 or 400 output impedance way too high for a 300 Ohm load. That would mean you loose 6dB of signal. For such a load you'd be better off with 100 Ohm or less, ideally even 50. Which would require a huge coupling cap, bad idea IMHO.
Thomas
P.S.: I think you should start to try more yourself instead of randomly picking schematics and wondering if they might work. Building such circuits on a breadboard does not take a lot of time, is a lot of fun and you will learn a lot. This will also enable you to ask better questions so you will get better advice