You don't ask for too much do you??? LOL, just kidding as that's why we're all here.
The most favored is a darker roast because the darker a bean is roasted the lower the acidity. Trust me, you don't want alot of acidity in a shot. The high brewing pressure will extract all the sourness you can imagine.
Regarding the grinder, that's like asking what is the best food to eat. Lots of good ones out there and it depends on how much you want to spend. My personal favorite is the KitchenAid Pro Line. It's well made, grinds great, can be modified for better performance and is fairly cheap.
The goal is to grind fine enough to slow the water flow down to extract all the goodness and nothing bitter. Much easier said than done though. Most home machines crank out 15 bars or so and it should be 8-9 bars of pressure for optimal flavor. Grind too coarse and the water will rush through and extract very little flavor. Too fine and you'll get slow drips if anything. There's no way to really explain it as experimentation is the key to it all.
I think way too much thought is put into shot timing and volume. Espresso involves LOTS of variables and getting the same exact result each day is nearly impossible. There's really no way a human can grind exactly the same, dose exactly the same, tamp the same way, etc. Just too much variation. It will get better with practice, but not perfect.
Say you grind 16 grams in a double basket, distribute the grounds, tamp, etc. and pull the shot. As soon as the good flavor is extracted and starts to blond that's it. Regardless of whether you have 1 oz. or 1.5 and whether it takes 15 seconds or 20. As soon as the grounds are spent that's all you can do for that particular shot. Later!