Here's the bike ready for a 3 days trip:
Total volume of the bags: 2075 cu in (34 liters) including the stuff sack
Total weight of the bags: 40,5 oz (1150g)
(My 35l backpack has 1230g)
The vinyl is on the heavy side, but is really strong, totally waterproof, easy to clean ant quite easy to work with. Having its own structure it stays where you put it
You don't need to hem the edges, just heat them with a lighter or you can do this if they start to fray.