Isn't this the sweetest thing

[Krabbe]

I've only recently picked up mixing more actively along the z-axis, to which reverb is excellent. As you have experienced, my main "obsticle" now is ... well, making the verb disappear and give it a natural feel. I am, in no way, on top of the process yet, so I am hesitant to use it, especially on a rather ... fragile mix as this. I would have loved to make it more 3D, but I have to surrender to the fact that my abilities doesn't suffice to do so.

I agree with your lean reverb approach. I've spent alot of time trying to get on top with using reverbs and it's a steep learning curve. Some of these types of songs I've had up to 5 instants of reverb simultaneously running. This has been more of an attempt at making the reverb effect itself disappear and filling out the performance with some natural realism whist controlling depth and position. Unfortunately the method is a bit hit and miss and the approach varies greatly from mix to mix, but with practice you do start to get a feel for it.

Some of the best jazz recordings of all time are in mono, so your direction here was more than warranted. The best thing about all of this is you had a direction that you followed through.