Hello Simon,
I did the whole deck with the Fein blades, but on a Bosch multitool machine. I got an adapter for it. I just measured the blades at home and they are 4,12 mm (outside width). They are original Fein and 184 HD is written on the blade. My boat is a Bav 38 2003.
It works very well, but you need to hold the machine very tight and keep very concentrated, because you cut very easy in the side of the teak. Look at the lines in teak and find the less risk direction. After you did the rough work with the blades you still need to sand the sides of the plancs. You can also the multitool for this work. Success. If you have to do a total deck, consider 200 hours of work including caulking and sanding after caulking.
Ger
