I tie jig hook fly patterns, but I do not use jig hooks. Instead I use a wet/nymph hook that is either 1XL, or 2XL, from the hook recommended in the pattern. I insert non-lead wire to the rear inside cavity of the metal bead head to center the bead head on the hook shank.

Most down eye hooks are at either a 20 or 40 degree angle from the hook shank. I bend the hook shank (using wire not forged hooks) at a point that leaves the correct space for a a metal bead weight. I do a 45 degree bend, this reverses the center of gravity on the hook, so the hook's spear is rotated to a upward orientation.

The fly pattern moves along the bottom with the hook shank tilted up off of the bottom and the angle of the hook's eye to the surface remains at a 45 degree angle. Two 40/45 degree bends are better at controlling the action of the hook pattern, then one 90 degree bend using a jig hook.