Why you should choose a lowpass configuration on your L antenna tuner

K6JCA has analyzed the needed components values for matching a load while moving on a constant reflection coefficient circle. The plot below shows that in case you select the high-pass configuration for your tuner, certain angles of the reflection coefficient will give you skyrocketing component values.

Component values for the highpass and lowpass configurations

Above you can see that the LsCp &CpLs configuration keeps the max component values quite flat. LsCp and CpLS  are therefore the best engineering choices based on cost and realistic component values.
http://k6jca.blogspot.no/2015/04/notes-on-antenna-tuners-t-network-part-1.html