I have used A-loops left side number plate 1 gal tank for HS on the YZ400 I used to have. If you are going up a steep hill and your main tank is empty, it can cut out because the number plate tank will be lower than the carb. The tank empties last, and on the MX course I could feel the weight out back a little. Also the subframe is not designed for that kind of weight, mine eventually failed at the seat mounting bolt, the tank came off and I DNFed that HS. I would skip that option if I were you. My friend uses the front number plate tank on his 250F, I think it is made by Acerbis. A 1.3 and a 0.8 gal are available. Some people say that they can feel the weight up front (I did not notice), but at least the tank empties first and there are no uphill gas starvation problems. He has probably done 10 HS on it with no problems, other than initial setup (getting the hoses to not leak). It is MUCH cheaper than the A loop tank. If you want a headlight though, there is a problem... The Enduro jugs that replace your crossbar pad work well, unless you have protapers. I have not seen a kit for the hose feed, which I assume would be like the front number plate tank. For HS, you might as well pit as carry these around and then stop to fill up. Could be okay for trailriding though. I have skipped the bizarre and gone mainstream with the Ty Davis 3.2 gal tank. It works well and I am happy with it.