I'm in the process of designing a weldment that will need to have two parallel linear guides (THK Style) mounted to it. It will basically look like an extension ladder laid flat, with the two rails mounting to the top of the main structural members. Obviously post-welding machining will be necessary to bring the two mounting surfaces into parallelism and some locating features will be necessary. Any thoughts on locating with a shoulder vs pins, and techniques used to minimize chances of binding after assembly? I'm also needing to nest a 1m long lead screw down in the middle of all this. Any thoughts?