I'm not an archer so I won't offer any advice regarding that, however I will say what I know with the gloves and helmet thing. As far as I know there's a set weight (I believe it's 10lbs or whatever unit) at which point your effective weapon proficiency decreases. This is dependent on the weight of your body, boots, gloves, and head armour all together. So when they say it's 2x and 3x they mean by the weight stat of that item. So as long as you keep all your armour under 10lbs you don't have to worry about it. I'm not sure just how bad your proficiency is affected by being over the limit but I'm assuming it's fairly negligible at lower values. Someone else could probably explain it all a lot better.
Edit: Actually forget my post and take a look at steevee's guide, that'll tell you much more than I could