The ULS has scrim in it and you will find some guys that prefer it over the UL that doesn't for structural reasons.
others say the UL glass is clearer and use it over darker wood veneers.
either way, you'll be hard pressed to tell the difference between the two.
i weight my smooth on at 100:83 ratio and it takes about 1600-1800 gains for a one piece bow, and less on take down limbs. i still mix up 800 grains total for a set of limbs and usually have a bit left over.
a pint should build 4 bows easily.... but you'll probably only get two on you first bows.... everyone uses twice as much epoxy as needed on their first ones...... buy rubber gloves bro.