A. That depends on what size ammo you're shooting, as well as temperature (to an extent); the heavier the ammo and the colder the temperature, the thicker the latex. It also depends on what taper you're using, in addition to your draw length. At Appalachia Sling Co., we offer 0.45mm, 0.5mm, 0.55mm, 0.6mm, and 0.65mm-thick latex, which caters to most shooters and ammo sizes.

For short-draw and mid-draw shooters: 

0.45mm latex can be used with 1/4" (6.5mm) steel up to 5/16" (8mm) steel and 3/8" (9.5mm) clay, using tapers such as 18-10mm, 19-11mm, 20-12mm, and 22-12mm.

0.5mm latex pairs well with 5/16" (8mm) steel up to 11/32" (9mm) steel, as well as 3/8" (9.5mm) clay using the same tapers. 

0.55mm latex is used by many shooters who shoot 0.5mm latex during the summer and who need a little more power during winter months. It pairs well with 11/32" (9mm) steel and target practice with 3/8" (9.5mm) steel.

0.6mm latex is primarily used for 3/8" (9.5mm) steel; good tapers include 20-12mm, 22-12mm, 23-13mm, and 24-12mm. 

0.65mm latex is used to hunt with 3/8" steel and to shoot it during winter months. Pair it with wider tapers like 24-12mm, 25-13mm, and 25-15mm for a formidable hunting setup.