If you sre looking to get a snug fit porch awning, you can use a small full size awning,measure from the ground at the rear of the van around the awning rail until just in front of the door, then add the measurement from the awning rail vertical to the floor, the total will be the size of awning you need.You then need to buy an adaptor pole from Isabella that comes with pads.You thread the awning into the channel until it touches the floor at the back,You then cut into the awning bead at the point where you want the front vertical drop to be, you then feed the awning bead down the adaptor pole and the pads press against the side of the van.The awning bead will be in the channel all the way round and down the back of the van so no draughts.Will only work with a poled awning,but will certainly give you what you are asking for, maybe worth looking on e bay for adaptor pole, that was where we sold ours when we changed to air.You may also find a suitable poled awning as small ones seem less popular.