The above three substitutions still allow you to improvise over the blues using the Minor pentatonic scale or the Blues scale. But be aware of these chord substitutions when they are used in a song. Knowing, hearing and reacting to all chord changes are the hall mark of a good improviser.

The Embellished Blues format dramatically affects the improvisation when using Mixolydian modes or other individual scales for each chord.

The scales used for an Embellished Blues in C for example are :

Audio 9.3

The scales used for the Blues in F are :

The scales used for the Blues in G are :

Let us compare the C- and F-Mixolydian modes for the Blues in C.

C Mixolydian mode :   C   D   E   F   G   A   Bb   c

F Mixolydian mode :   F   G   A   Bb   C   D   Eb   f

You should identify the notes which are different from one scale to the next and focus on those in your improvisation.

Going from the C- to the F-Mixolydian mode (or vice versa) these notes are the E and the Eb.

C Mixolydian mode :   C   D   E   F   G   A   Bb   c

F Mixolydian mode :   F   G   A   Bb   C   D Eb   f

C Mixolydian mode :   C   D   E   F   G   A   Bb   c

G Mixolydian mode :   G   A   B   C   D   E   F   g

G Mixolydian mode :   G   A   B   C   D   E   F   g

F Mixolydian mode :   F   G   A   Bb   C   D Eb   f

You can easily identify these notes for the blues in any key, for they are the 3rd and b7th of the I7 chord.
The 3rd is flattened and the b7th is raised.

For the blues in C :

For the blues in F :

The best way to incorporate the Critical Tones in your improvisation is to practise them as sustained single tones over the Blues progression.

For the Blues in C :

Audio 9.4

For the Blues in F :

Audio 9.5

Chasing the Blues is an embellished Blues in F.
Observe how the Critical Tones (A, Ab, E and Eb) are incorporated in the melody line.

The notes on offbeat 4+ in bars 1 and 11 (shown in red) are anticipations of the critical tone for the chord in the next bar.
These melody notes are running ahead of their tonality so to speak, and are being "chased" by the chords of the Blues progression.
This type of chase produces extra energy and drive to a song.

Melody

1.
Explore in your improvisation the use of the critical tones.
First practise beginning each new phrase on the critical tone of the appropriate chord.

As you get to know these tones intimately, you may start phrases on other notes of the Mixolydian mode, but always include the critical tones within your improvised line.
Remember they are the only notes that express these short "modulations" of the blues progression.

The Critical Tones Principle does not only apply to the Blues but to all Jazz improvisation.

2.
Swapping 2s and 4s on the embellished blues in F : complete improvisation

A.
C instruments - practice the critical tones in long notes for the Blues in F, in C and in G

Bb instruments - practice the critical tones in long notes for the Blues in G, in D and in A

Eb instruments - practice the critical tones in long notes for the Blues in D, in A and in E

B.
The same exercise as above but this time use some rhythm patterns (9-16 or 17-24)

C.
Continue practice on the Mixolydian mode in all keys.