The fourth option to solo with a tritone sub is to use the Mixolydian mode (1 - 2 - 3 - 4 - 5 - 6 - b7). It has the same note as the major pentatonic scale with a fourth (4/11) and a seventh (7).

The fourth of Db7 (Gb) must be treated as an approach note.

The seventh of Db7 (B) is the third of G7.

You will find below 6 easy jazz guitar lines using the four previous scales to approach tritone substitution. You can hear these 6 licks in the YouTube video at the top of this page. You can also download the free PDF by clicking on the picture at the top too.