Want to buy first awning for our wee fleetwood colchester. Confused.....we tour so what's best Polyester or Acrylic, we have so far been led to believe polyester. Also size of awning, we have measured as indicated in all instructions and come up with 800cm but some companies have sizes which split at 800 ie. size goes up to an 800 and next size starts at 800 what one should we go for. Hope you can clear our minds.