70cm fin for F-Type 158?

[kimax]

Hi there! Need an advice.

I'm using my F-type in 3-9m/s wind and a little choppy water with Gaastra GTX 10.5m2 sail. My weight is 70kg. Will I benefit in perfomance by upgrading my stock "Drake R13 Race NR 640" to "Drake R19 Race NR 700"?

Early planning in lightwind is what I'm looking for.

Thanks in advance, Max