For your assorted questions about stitching, you can get a lot of info by searching the forum.
As for the weight, I started out with a Panosaurus (2 lbs.), which is a super cheap, but somewhat cumbersone and flimsy pano head and once I understood the basic principle, I made a series of better and lighter and more compact pano heads. I now mostly use a 3.5 oz. carbon fiber pano head I made and that I've glued to my 1ds permanently. It's only suitable for single row vertical stitches and only for my 50mm and 35mm lenses, but it's very effective and setting up is no hassle whatsoever, since the pano head is now essentially integral to the camera. I've shot thousands of pano images and I'm presently in the process of assembling a lot of final images with the PTMac program. This is working super well, but there's a big learning curve and also some clumsy implementation and bugs to work around. Pano head is much more versatile than stitching shifted images from a shift lens, since this severely limits how wide you can go. With a pano head it's easy to go 360 degrees. Most stitching software doesn't work well (quite poorly, actually), so many people insist that good quality requires the shift lens method. This is no longer true. If you can endure the learning curve and hassles, PTMac certainly gives spectacularly good results. Perhaps PTAssembler is just as good, but I haven't tried it for quite a few months.
In any case, there's no way to do consistently high quality panorama stitching easily.