I have the Iberital Challenge and I would certainly say it is a reasonably noisey grinder when it is grinding. I only grind for espresso so couldnt correctly evaluate if it is noisier compared to a coarser grind. I think it is a bit of stretch to say that the grinder was set up for an espresso grind from the shop, it needs to be set up to your machine and will require adjust between different origins and as the beans age so is not really a set and forget kind if thing. So dont lose heart, believe me sometimes I feels like you have to turn the adjuster alot to notice a difference and I think you just get used to getting close to the mark the more you use the grinder.
I cant really comment on whether your machine is in specs as far as the noise you are going so I will leave that alone.
As most people on here will suggest always use the double basket even if making a single shot, is easier to get consistent shots.
Use the 30 seconds or whatever as a general rule to set up a 60ml shot for the double and than adjust the grind/tamp whatever from there to adjust the tase. You may need to pull the pin on the shot early so it doesnt blonde and that will affect the taste and may wreck what would have been a good shot.
The advice given to me that worked when setting up my grinder was to always inspect the puck after the shot and only adjust the grind once you are satisfied that the dose is correct and consistent.
I dont know the machine you have so cant comment about machine specific but it sounds like it may have a lower showerscreen like my expobar. I will run through how I dose mine but may not work for you. The credit for my dosing has to go to 2mcm (Unless I muck it up and than the blame is all mine ;)) and modified after doing s course with my machine in Sydney. I grind the basket so it is half full (unless you are a basket is half empty kind of person ;)) than tap the portafilter on the bench a little than grind so there is a little mountain and tap on the bench again. Than I level it with something flat than use the tamper weight. Than refill and level with flat object again, than to compensate for the lower showerscreen I use my index finger sideways and use the curve of my knuckle to remove a little bit of coffee, this seems to be enough to allow it to still slot in to the grouphead. Than I tamp.
Hoepfully I have helped in some way and I am sure some more experienced campaigners will correct me where I am wrong and point you in the right direction.
Dont despair I am sure you will get there and be impressing people with your coffee in no time, and most importantly impressing yourself. I am sure you made the right decision on machines. Hopefully you will find a place to give you suitable training, which is key to improving your coffee in my opinion.