I've read the thread three times! I'd also like to know the total overall project scope! If precision placement is the goal, I'd paint it up on the ice every 50-100'. You could use a transit! Then use a power ice-fishing auger to drill holes at desired intervals. A concrete block, cord, and bleach bottle would mark your control points. Heavier weights with cables could be used at corners, etc. In the spring, you could fuse, glue, connect your lines and tow them out to the control points. once the network is floating in place, flood it to sink. Dependent on the water depth, and surface bottom, I can't see that you'd get it laid out more accurately. On a river crossing I worked on, the line from the concrete block is passed thru the bleach bottle handle then connected to the anchor line with a heavier clevise. The clevise slides down the anchor line (working against the bottles bouyancy and takes the slack out, so the floats line up perfectly! If you go with this, you may want to add a little RV antifreeze to the bottles, so they are just bouyant to 2-3" above the surface. That might keep them from being pulled around during the ice break-up! ~Scotty