I'm on my second Fiamma - first lasted 6 years with considerable use (100+ nights/year). Excellent but be sensible in high winds.
Always fit a tie down strap. The Fiamma rafters and OK but much better and much cheaper is to make you won form washing line telescopic poles as availabel in most markets.
Saw off the top of the nylon hook meant to hold the washing line. Drill dwon into the remaining plug and inseet a round galvanised nail (drill hole well smaller than nail). Saw off flat head of nail leaving about 1 inch spike. This fits into hole in centre or roller and on each upright meant for rafters. At other, ground, end of poles, increase diameter by wrapping round insulation tape until a nice smoot fit into rubber suction cups sold to fit awning poles. These go against caravan side in pockets in the awning bag. These poles are easy to tension and do not loose their tension as the Fiamma rafters tend to.
Finally, buy one size larger than you think you need, so long as you have at least this lenght of straight rail along the top ofthe van.