In general, a bow won't make any more noise if it's tillered from 3 under than it will shot split if it's tillered for that. You can usually overcome the difference if you're shooting 3 under on a bow tillered for split by raising you nock point about half the thickness of your ring finger on your shooting hand.
I've shot two under as well and often do on bows 45# and under. When you get up over 50# it's a little hard on just two fingers - tend to get a little numb if you shoot very long - so I go back to 3 under on heavier bows. At 43# you should be able to shoot 2 under if you want, get the benefit of having the arrow close to your eye and, at least in my experience, get less string noise than from 3 under. I think the reason three under is noiser, at least for me, is inconsistent placement of the ring finger - if I make sure I get the same hook with all three fingers the extra noise pretty much disappears.