>>1371328look for a waterproof one with a grommet layout that you like, not that hard.
a buddy of mine like using ones for motorcycles as they arent rectangular and fitted for hight, he would sow on an extra gromet on top, not worth it imo
the "best" tarp for winter i would say is something a bit larger then you would use year round, a more important question would be what pitch is best suited for winter, if snowfall, you need a more enclosed but heavily slanted pitch, so tying it off higeher might work for you unless you are also combating wind
in my experience tarp camping in winter i would go with a fully enclosed pitch, with high slanted walls, you minimize on space, but maximize on heating and stability
