Loads on a sail and rig are determined by the "stiffness" (righting moment) of the boat, not by wind speed. If you heel the boat to 30 degrees in a gust, the load on the sails and rig is the same whether the wind is blowing 8 kts or 30 kts.
An Oday 27 is a 7000 pound boat with a lot of ballast. It's a stiff boat, with a high maximum righting moment.
4.93 (4.7 smoz) is not the right dacron for a furling 135 for a stiff keel boat that weighs 7000 pounds. It will stretch out quickly in winds that can push the boat to hull speed. 4.93 would be okay for a 135% genoa on a 2000 pound 20 footer, but not for a 7000 pound keelboat.
5.53 would be the lightest weight I'd recommend for a light to medium duty #2 135%. 6.53 dacron would be better for an all-purpose furling 135%, that can be furled to the size of a #3 working jib.
Judy B
retired sailmaker