Good questions, and the best answer is what works best for you. Everyone will have their own preference. I like to have a front/rear combo such that there is just a small amount of light between the two, which makes sight alignment easier. Whether you like a wide or narrow front sight is really a matter of preference. Your brain will naturally find one or the other easier to align more accurately.
I have the Meprolight Tru-Dot tritium adjustable sights on my G20. The front sight is 0.160" wide, but it almost completely fills the rear sight at arm's length, so it makes sight alignment very easy and natural for me. This was a compromise for hunting/range and carry, though they aren't really ideal sights for carry since they stick out a bit and are close to the end of the slide. It's a better choice for hunting/range work than carry, but I make it work for both. Even though these sights are well made, if your use was strictly for carry I would stick with non-adjustable sights mainly for the "simpler is better" aspect and less chance of failure.
The top of the front sight for my Meprolights is 0.305" above the slide. This is really high compared to the stock fixed sights, but I think it's somewhat necessary to provide enough adjustment range for elevation, plus the adjustable rear sights are just going to be higher due to the extra hardware involved for an adjustable sight.
I would definitely go with something adjustable if your main use will be for hunting.
A handgun is only good for fighting your way to a rifle.