Thats why I suggest a staysail. You may want a bigger genoa in the light but can't really expect to go from 500 sq ft to 125. My understanding is sails are designed for limited ranges. A 130% may be ok in the light but even reefed to 100% is unlikely to have a range 5-20 without stretching. 18 knots with a 100% plan is not unusual. My query is what is your plan at 25, 30, 35 and 40.
I know the main is reefed first but there is a limit both to sail design speed and boat balance.