cheers, basicly, when making your kicker, depending on your height, for example, that smaller one is 23 inch by 4foot long, with a slat 1inch x 2inch crossing the sides every 2 inches or so depending on the thickness of the wood you use for the top of the ramp, which can ethier be 2 3mmply boards, or one single sheet of 8mmMDF, Which i used on the bigger latest kicker, its harder to screw down, but feels solid and is very long lasting.The dimensions of the bigger take off kicker, are 3foot x 6foot long, that is a fair big one and is light. i have a video showing, roughly the shell of the kicker, and cutting out the sides etc, the link is here www.youtube.com/watch?v=B8-5kjmRC2E Good luck with building yours mate, if you need any help, or questions about the thickness of wood or anything, screws etc, just message me, cheers mate
Id also recommend putting some casters(wheels) on the front of your kicker, so much easyier to move, as they do weigh a fair amount, you can see on the end of the bigger kicker cheers bud

 How Did You Make Your Kicker?? Can You Give Me Some Demensions Because I Am Makin One For My 4th Year Project At School.. Nice Kicker BTW