building polytunell/greenhouse hybrid

im in the process of building what you could say is a greenhousr polytunnel,it is 7ftx5ft the sides and rear are made from reclaimed sash windows roughly 3 half foot high to the sides ive attached 3 hoops to make the tunnel one at front one at rear and one in middle to the peak of hoop is 6 half foot im looking for something suitable to put over the hoops and was wondering if this would be suitable http://www.ebay.co.uk/itm/Clear-Polythene-Plastic-Sheet-TPS-4m-x-25m-roll-/110513706980?hash=item19bb2157e4#ht_320wt_899
ill post some pics asap to show my hybrid as I progress lol

was wondering if this would be suitable

That plastic doesn't look heavy enough to me.