That's not really playing outside. Sounds like you're trying to talk about playing chord scales, but in the first bar of your example, that's not gonna work too well unless you add notes. The D dorian scale you mention for D-7b5 needs the lowered 5th to go over your chord. You can ignore the #9 in the G7 to just play G mixolydian, though. Then you'd use C mixolydian on C7 and Bb Mixolydian on Bb. However, that approach is ignoring the larger harmonic context of the tune.
Assuming this is a loop, the tune is in C with b7 in the key. So you'd approach the first 2 chords like a minor ii-7 V7, resolve to C, but then treat Bb7 differently, playing a scale built around the chord tones, with the passing tones coming from the key of C: Bb C D E F G Ab Bb (lydian b7). All that is very INSIDE the chord changes, but that needs to be understood before playing outside. Alternatively, you can construct your phrases around the chord tones and not worry about the scales.
There are many ways of playing outside. From a purely melodic standpoint, applying atonal melodies creates an "out" sound. For instance, playing around the cycle of 5ths consecutively will create alternating tension and release by leaving the key and returning to it.
From a harmonic standpoint, playing outside can be done in a staggering variety of ways, but they generally come down to: A) a specific chord substitution that you know works well and sounds good over a different chord, B) choosing a chord which provides tension differently from the original chord before resolving to the original chord of resolution or C) playing through a harmonic cycle (half steps, 4ths, 5ths, 3rds, etc.) or harmonic pattern (e.g., Coltrane changes).
Using your example, playing outside using option A might sound like: F-7 Bb7#9 / C7 Bb+7 /
Option B might sound like: D-7b5 Db7 / C7 Bdim
Option C might sound like: Bb-6 F-6 / C7 AbMaj7 EMaj7 C7 /
Etc.
Basically, start looking for things which rub against the chord changes when you hear them, figure out what's going on, and if you like the sound, practice it and add it to your arsenal.