Soloing Over 12 Bar Blues

I've been trying to lock down what kind of scales to play when playing over the 12 bar blues. First I played straight pentatonic minor, sounded kinda boring, but it worked, then I found out that to capture more of the blues flavor you want to add the major 3rd and 6th. Then I found out that when the rhythm moves to the IV, you should switch keys, so in E, when you move to the IV you would play in A and likewise over the V you'd play in B. But this is where I get a little lost. Over the I you would basically play the E blues scale with the major 3rd and 6th added. Over the IV do I do the same thing? Is it just A blues with the major 3rd and 6th? Same question for the V.

I've seen lessons/articles online about licks to be played over the IV, etc, but I'd really like to know what my note options are so I can come up with my own.