Just got back from a week's hols to make the following (hopefully useful) observations:
1) Siliconing a toilet (with a 12x8" or so base) down to perfectly clean ceramic tiles works (just as others said it would). Even with 2-3mm of low modulus silicone (Siroflex "trade strength") squeezed well under the edge (which is about 1cm thick on mine) after a week exhibits no noticeable elasticity whatsoever. It might as well be araldite for all I can tell, except silicone has the chance of removal without floor damage. No screws at all. Might get less mileage from a loo with a small base. Using a high modulus silicone *might* get it fixed firmer quicker. I gave it 48 hours before serious use and a week seems to have seen it set fully.
2) A high level flush is well worth it IMHO. The flush is about 1/2 the volume of an old 70's cistern, but certainly clears the bowl in one. Noisy mind, but function over form in my house :)
3) A well made bog with a decent smooth wide throat is also well worth it - no jamming apparent yet (got mine from Bathstore.com). Using 110mm couplings as close to the loo as possible might be a helping factor too (I found a 110 spigot elbow where as soon as you are past the spigot collar, it is the full bore immediately. Much more convincing than those daft restricted pan adaptors B&Q sell that seem to be 80 odd mm all the way.
4) A Fluidmaster Pro float valve seems a very nicely made bit of kit. Brass thread, twist-lock easy to uncouple internal mechanism (ie whole internal lot comes off without a spanner, for servicing). Quiet fast fill from 4 bar mains.
5) A Floplast 110mm AAV is quite "blurpy" when it opens, but you don't hear it over the flush in my case. A smaller AAV or a HepVo might be quieter.
Anyway, hope those snippets are useful to someone...
Cheers
Tim
-- Tim Watts