Hey there. Confident intermediate winger, 3rd year, 85-90kg depending on season, currently my only board is 90lt midlenght and only foil Code 850s, mainly chasing messy Mediterranean waves. Generally I prefer to keep things simple but in high winds and chop my midlenght board becomes quite handful. Never had a sinker, but I have a chance of getting dead cheap North Swell 2021 5.4' 51Lt in good condition. I was actually thinking of getting something around 65Lt until this came along. Would this 51Lt be too small as a 1st sinker for my weight? I would be using it only in high 20s and 30s.
Thanks

If you have enough wind the sinker boards become extremely easy to start with tons of chop. The board sits so far under the chop I find it easier than a board that sits at water level or above. I'm 77kg and use a 54L and it fully sinks with my weight. I can stick both feet in the straps then start. I think you can do it, just expect to fall during the start for the first session or two.

That's a VERY sinky sinker. IMO that's way too small especially for a first time sinker board. For reference, I'm 62 kg and use a 30 Liter board but it takes a lot of technique and fitness to get going, uses WAY more energy, and you have to simply accept that you will be struggling in the water while everyone else is up and riding.

86kg here. I miss the efficiency of my 85l midlength but am riding a 77l midlength most days right now. I also have a 65l that's fun but it definitely leaves me waiting in holes for gusts if I fall in the wrong spots and I'm less confident exploring on it. I'd want to try a 51l before I bought it no matter how good the price was because I expect I'd struggle to use a 3m with that board in 20-30 knots and I'd hate to have to use a 4m.