My uncles model 98 (not custom) with a 4 power scope.
10" DYE Excel
20oz Anti-siphon tank
BSA 30mm red dot sight 5-MOA
Easy to sight, quick accurate
With the 30mm you can easily point and shoot. It works the same way a shotgun bead does. You put the dot on your target and fire. This thing can be bought in 42mm and 30mm objective lenses and can be bought for the 7/8" Weaver and the 3/8" Dovetial mounts. The 3/8" Dovetail is on any paintball gun with a standard sight rail. The Weaver is on the Flatline.
If you want to be able to aim at people easier, get this. It does not replace skill, and does not actually make your gun more accurate. But it is great.