1 - PRACTICE! 2 - Based on preference... mine's using polys, starting from a simple cube. 3 - Make sure in your options that you've unchecked "Keep Originals." As for the extra isoparms, if the 2 halves are exact duplicates, I wouldn't think that would happen, as they'd have the same number of spans and such. The mirroring could possibly have switched the surface's direction, however, so check that.