The final step in learning to play over a constant bass regardless of the rhythm is to be able to play licks freely with the fingers while maintaining a steady, driving bass. Start with simple licks derived from the minor pentatonic scale or the Blues scale and gradually increase the complexity as you become more comfortable.
The aim is to eventually be able to play licks, chords or whatever you choose in any rhythm over the constant bass without losing your timing or missing any notes. Here is a Blues in E which uses a shuffle bass and features both licks and chords over the top of it. Be patient with it, practice with a metronome and isolate any difficult areas to practice separately.
The key of A is also good for the constant bass style, because the root notes of chords I, IV and V are the open A, D and E strings. Here is a Blues in A which is played with straight 8th notes. Once again, take your time with it and isolate any trouble spots to practice separately.
To finish things off, here is a Jazz style Blues solo inspired by the playing of Joe Pass, Herb Ellis and Kenny Burrell. It Can be played either with a pick or fingers, or a combination of both. Having completed the book, you should now be an excellent Blues guitar player. The best thing to do now is to get out and play with other musicians as often as possible.