I do not think, that formula n5 can be called distortion. Yes, it's pretty high gain, but not in distortion feel. More like fuzz face, because still has all dynamics and not as aggressive. I like to have some pedal after it, because you had all that dynamics and feel right. WIIO for "bigger" sound, DLS for more tight and mid-focused.
And also, I think, that this pedal LOVES single colis, and tele. Before 12:00 it's nice crunch like black crowes. After it's Billy gibbons style even on tele, and I can say, that it's more Gibbons style on tele, then with humbuckers. But not for AC/DC, because they have more focused marshall crunch, which not a FN5 type sound.
So, I do not say, that this pedal for everyone and every sound, but if you like that type of sound, you will love it. And should try it for classic rock.
Also you can check it's sound on tele with gain on 3 o'clock:
P.S. Tomorrow I'll try to put p-90 in neck position of my tele, and I'll write about my impressions.