I have never seen a square taper spindle less than 103 mm. A quick check with my Sutherland's 6th ed. confirms. A 95mm spindle (if you could find one) in a 68mm shell doesn't leave a lot of taper exposed to mount a single crank let alone a triple. If a 103mm spindle is too wide for a proper chain line, I'd suspect an alignment problem in your rear triangle.