need dimensions scale tarp,bed roll

[tdodm]

im gunna try and make some tarps and bed rolls for my venom safari
ive all ready got a bird feeder roof rack with some straps and bungie cords... even a scale looking tot for them... but i need help on the bed rolls
fer 1/10th size the dimensions i figured out from a full size one on walmart is 7.7"x3.3" but that just seems big to me... any one have dimensions for one?
also im looking to make a rolled up tarp for my rig and was wondering what dimensions and fabric to use on that... any ideas? the tarp and bed roll will likely be rolled up all the time in the rack or scale tots i have

 

[T_Baker]

for the tarp, i just used a thick/good plastic bag cut to size. its rolledup and tied. my tarp is white.