if you are truly looking to buy a unit to view either one of the items metioned then i can promise you that you need to get a bigger screen, 10'' minimum, you can buy smaller, and say you have such and such but to actually get your moneys worth and utilize the unit you need to be able to see the info its showing you! i speak from experience brother and am just trying to save you money in the long run, you'll want a big screen front and back, especially on the bow where its further from your face, and i don't think your eyesight is improving, so "future proof" by going big