Hello.
I don't want to labour the point, or sound too pedantic but:
If you use wet and dry it'll stick to the bed with just white spirit to wet it and give a bit of suction to the paper. No clamps or glue needed and easy to clean off
Even water will stick wet and dry to a planer bed, but neither this nor white spirit will stick the heavy, cloth backed abrasives needed for the initial flattening when lots of metal needs to be removed. If you have something posh like a Lie Nielsen, then just a light polish with fine wet and dry is all you'll need, but some Stanley and Record models can have hollows as much as 5 thou. this would be too tedious to do with anything finer than 80-100 grit, for the first flattening. And of course flatteming on glass on an mdf platen will need clamps.
Chattering usually means you are doing something wrong - too much set, too loose lever cap, workpiece not solidly held. Not an excuse for the credit card experience!
All true, but the flatness of the bed of the frog is critical. The lever cap cannot firmly press the blade assembly to a frog with a hump in it--as they often have--or lumps of enamel and burrs around the edges of the casting...
I expected A2 to be difficult but in fact it sharpens really well freehand on a fine oil stone. Complete surprise after everything I'd read. Just one stone is all you need, no grinding needed if you do the convex bevel thing.
A plane iron really should have a CONCAVE bevel (must be done by grinding) or a dead flat bevel (achieved with coarse stones or abrasives on a flat surface again) with the secondary bevel honed with a very fine stone. Only oilstones such as Surgical Black Arkansas or Translucent Arkansas are fine enough to hone a really sharp edge and trust me, these take too long for A2. If you only have one stone and can remove metal with it, then it is not either of these and not fine enough. Before anyone mentions it, shaving hair from the back of your forearm is not a good indication of sharpness. Blades which are only moderately sharp will do this, too, but suck wind when used on wood.
PPS seating on the frog is not too important as long as the blade is firmly nipped between frog and cap iron + lever cap, as close as poss to the cutting edge. The lever cap does need to be tight enough to press the blade down flat on the frog, but it's the edge grip which counts.