Rf matching is not a simple task but it can be done

Usually after all calculations is done there is always some tuning because there is components which is not taken into the formulas and can not cause they are hard to forsee.
Even skilled rf technicians got to do some work after he or she has done all calculations.
Rf amplifiers usually work well with both 50 and 75 ohm cause the missmatch is low.
To get most of your power out in the air you have to make the transmitter looking into a well matched antenna otherwise big losses is to be expected.
If you plan to use a long feeder use one with as low losses as you can afford, coaxial cables aint cheap, at my setup I got cables that cost lots of $ because I don't want to lose any power though there is plenty of it ;D
As long as the feeder is short there is low losses but with increased length the losses gets quite big if the missmatch is severe.
Your transmitter is probably not so powerful so keep all this in mind.
I used to say that if you go by the book all the time you will never get anything done most of it is only suggestions ;D
Rf teqnicue is very interesting and veru confusing I would say ;D