...and here it is ! - finished the knife, you can't see from the angles but the top is bang on level with the uppermost slice of the blade at the full displacement, and both disappear through the insert simultaneously.
The knife is closer at the bottom than the top, the curve was for a 50mm larger blade, slightly more than 5mm away right at the top, is that a problem ? - there's a little bit of play on the bottom bolt so I'll be able to lean it to bring the top a little closer and file down the back a little so it doesn't poke up.
Only just slotted it in, not tried it yet, I have a load of cuts to make today that have been piling up in waiting !
Darn, my maple zero clearance insert is now a little bit of clearance insert - I want to make another anyway as I messed up the hole placement slightly on that one, I have to do the right hand bolts first or they don't seat properly.
I'll assume that every cut is going to kickback for a while, I always have a face shield, use a grr-ripper when I can and stand aside, but very wary !! - it was still bang on after the drilling but not checked it still lines up post final filing but I shouldn't have bent it, it was mainly front to back pressure and I'm no Hercules.
So now I have a choice of 40 and 24 tooth blades of identical diameter, kerf and plate (I got a Freud 2-pack), the blurb says one is excellent at cross cuts and good at rips, the other, the other way of course - but if I can't be bothered to change blades for /every/ cut, am I right in thinking go for the 24 tooth as a general purpose blade so it can still clear the bigger chips I'll get from ripping and slightly sacrifice cross cut quality - then change to cross cut blade if quantity/quality of wood to cut justifies it - and always change back to the 24 for any non-trivial rip cuts.
Added a photo of the knife and blade from as directly above as I can, the measurements/stats say 2mm is a good size, but nice to see it confirmed by eye, happy with that.
A little later, done some cuts and wow, so much quieter and smoother. See third photo of comparison, top one is Freud 40 tooth, bottom is supplied 24 tooth, feels planed smooth to the touch
Thanks very much to all above for the hand holding, am really pleased with my new saw !