Sounds to me like you have some crud in the needle and seat valve, that isn't letting it shut properly. It is allowing to much gas into the carb
. The other symptoms(besides leaking gas on the floor of your garage, sound like it is getting way to much fuel. I would think if you can get the needle and seat issue cleared up, most of your other problems should go away.
About all you can do, is take the carb off the bike, remove the bowl, gently remove the float without bending the tab, and clean the needle and seat out real good or just replace it with new. Put it back together, check your float level with the Odo upside down carb method.
replace the bowl, and put the carb back on the bike.