I absolutely agree with the safety factor of weed fins. I have tested by myself in the past some real "landing" in something between a shallow water and a sand bank with a film of water, and the stop was waaay safer than some stop with a straight fin on our s. Croce Lake.
You can also add the fear of some forbidden deposit of stones and debris that some criminals use to leave sometime in the lagoon, and you can understand why even in the deeper zones I don't feel safe planing with a straight 70 cm fin,
Already seen the super nice formula duo weed, absolutely a must but with the price of all formula fins, even slightly less, but not really affordable for me, think that I've spent almost the same for the whole Formula wood 158 board, with 70 and 53 fin and new boardbag, and for 100 euro more they "left" me all the other stuff, an almost new Fiberspar All Carbon 220-258 boom that I'm really happy to keep for me and use here, and 9,8 Gaastra Nitro 5 +Ignition 520 100% combo that instead I want to sell.
So I'm convinced I won't add any new insert until I try the board with my camless 9,5