The thickness depends partly on the material (the higher the index, the
thinner, but lens quality also decreases). For your Rx, a 1.60 index would
relatively thin. Polycarb (1.59) is often used for drilled rimless frames
because of its high tensile strength, but the optical quality is less than
1.60 plastic, which bothers some people more than others.

Also, the lens design impacts thickness, such as spherical, aspherical, or
atoric (in increasing thinness). You probably would want aspherical.

Check out the google group archives for recommended rimless frames mentioned
by others previously.

What is too thick? I grew up when cost, not vanity, was the major
consideration.

Bill