Watch the Applying The Box C#m7 - F#m7 - E/F# online guitar lesson by Robbie Calvo from The Power of Five
As you guys already know, a Phrygian progression is a chord progression that resolves to the 3rd chord in a major scale and has a characteristic note of the b2 (b9).
We are going to use 4 pentatonic scales over this progression with a little twist in the proceedings. The obvious first choice is going to be the C# minor pent, no surprises there. Our second choice for a really nice variation on our licks is the F# minor pent and the 3rd choice is B minor pent. The B minor pent will give us that b2 characteristic note but doesn't give us the C# resolution, so you'll want to combine B minor and C# minor pents to stay inside the melodic framework.
The 4th option is G# blues scale which will give us the b2 and the C# over our Phrygian chord progression. Remember that a blues scale is a minor pentatonic with an additional b5 interval added to it.
Let's lay the G# blues scale out and do a C# Phrygian/G# blues scale analysis.
C# Phrygian = C#-D-E-F#-G#-A-B
G# Blues = G#-B-C#-D-D#-F#
So what happens if you land on the D# in this C# Phrygian progression? Well, you try not to! Use the G# blues option as a really nice way of targeting the characteristic b2 and root in the same pentatonic based scale.