I would actually try and design so that most of the possible positions that the player can have will look good composition wise! In this case it is easy enough- just a corridor, so they can only walk up or down it! However for larger games, especially open world settings, this can be a much bigger challenge!
I’m currently running a GTX 980, an i7-5930K and 32 GB RAM! Yep these specs have been consistent, but for example, the indoor scene that I last posted runs easily at 80-90 FPS, whereas the grass scenes can go all the way down to 30 (depending on how dense I make the grass). The thing about realistic grass is, that if you want to emulate nature- you need a huge amount of blades- in reality grass is extremely dense, so most games tend to make the trade off of less blades for more performance, which usually doesn’t end up looking very real! I don’t think hardware really is at the point yet for games to run grass at the density required for realism, but certainly if you are creating your own archviz or realistic scenes, you can crank up the detail, as you can push performance much more!
No reason here other than my being greedy and thinking “more bounces = better” 
I’m sure the quality difference is very slight, but for me the build times are reasonable for most of my scenes, so I keep it at 100!
I decided to invest in a 4K monitor as I’m starting to ramp up production for my game (targeting 4K and VR). It also allows me to get much closer to a cinematic image, as many of the problems in game caused by lower resolution (like noisy aliasing on thin foliage) are made a lot better. Doing some quick tests on an older scene, it really makes a big difference in terms of clarity- no need for Temporal AA, so everything comes out looking super sharp!
I haven’t forgotten about the tutorial that I promised, I’m currently finalizing my photogrammetry/foliage pipeline and will be posting results along with a tutorial/free example scene here soon!