Sorry about that I am guilty of not reading the thread completely. (Hanging my head in shame.)
Not at all

. While the mods function together, actual gameplay results haven't been discussed much, afaik.
Both mods have their own rules for tile acquisition and release. This mod's is pretty specific (see the details in the first post) and doesn't take into account the possibility tiles may flip back due to the culture ratio (it's designed for vanilla mechanics). Instead, it uses a distance based formula to determine borders after war ceases. That's great, because (under vanilla conditions) you can go to war for territory and plan around those rules.
Using the two mods together can yield some interesting results with a LOT of (re)flipping occurring during a war. Maybe too much for personal taste, unless you tweak some default values in cultureDefines.lua (for Cultural Diffusion) to make it more stable. Not that the more random nature is a bad thing... but what happens is that, on conquest, you effectively override tile ownership due to culture and then immediately reevaluate that at the end of the turn. This is, of course, assuming you have tile flipping enabled
Look into both mods' lua files to see how they function and what can be easily tweaked. Both are well commented. IIRC, Cultural Diffusion has a 'tile lock' value which locks ownership for a certain number of turns after conquest (a rather high value... 10 to 15?). That setting would be inactive with the tile conquest method disabled in favor of Hex Conquer and Release. Thus, you get constant flipping and a ton of notifier spam. At least, that's my impression of what happens.
I would suggest setting up some quick duel type map conditions to try both mods alone and then together to observe the results and get a feel for what happens in combination (and what might need adjustment). Just started doing so myself after not playing for a while.