The gauges look flush, but actually they are a raised a couple mm to allow airflow through their vents.  I compared with another hygrometer and it looks like mounting them as I did slows the response of the hygrometer and probably the thermometer down a bit.  But it's only maybe 15 min behind one that isn't mounted, and for case humidity we are wanting to see more the long term environment anyway.

Mounting the gauges like this in a foam "noob" case is real easy.  I think anyone could manage it in a few minutes with an x-acto knife.  Mounting th humidifier through the wall of th accessory compartment like I did was a bit of a pain, because that ended up being one part of the case where they used some actual wood.  I ended up kind of butchering the lining in the accessory compartment because I really should have taken the case apart for that part of the mod, but I didn't think there'd be any actual wood in it.  I thought I'd just be going through foam and maybe a bit of cardboard.  With the angle I was trying to work at, it would have gone much better if I'd taken the case apart and done all the mods plus maybe some others and put it all back together nice. 

But even just the gauges would be a good good project for anyone wanting to upgrade a cheap case a little, and that part was very easy.

I am still thinking about an in-case "play in device", maybe that could double by playing quiet click tracks or accompaniment tracks while the case is open and one is practising.  With a little mp3 player or other small media player, that could be a seriously "deluxe" option for portable practice or quiet performances for just a few people.

Overall, I am pleased with how it came out.  It was a couple hours of fairly easy work and I like how it looks.  I'd decided a hygrometer and humidifier were worth having, and since the thermometer came as part of a set with the hygrometer (from a pet store, the set was less than 10$), I figured it wouldn't hurt to have one even though I don't think a thermometer is as important in a case as the hygrometer.  But having decided they were worthwhile, it made sense to me to build them in, rather than having them rattling around loose in the case where they might eventually scratch the violin or get damaged.