Afer much experimentation, I can now present a summary of the process I now use religiously for painting NMF.

1. Be very careful in construction, i.e. if necessary, clean up all seams and gaps with a smooth filler (I use super-glue as opposed to a "shrinking" filler/putty which may have a "flat" or "grainy" surface). Be warned that any "less-than-perfect" seams and gaps will stand out like a sore thumb under any NMF.
   
2. Before painting, sand out blemishes and scratches with 1200 and 1600 wet-and-dry sandpaper.
   
3. Tamiya Plastic Polishing Compound is then applied with an old soft rag to polish out any remaining fine scratches. The "white powder" residual can be removed from recessed panel lines by rinsing in soapy water and scrubbing with an old toothbrush (if still some residue remains then remove using a wooden toothpick).
   
4. I’ve settled on the Floquil metallics for my NMF. I mainly use "Old Silver", however "Bright Silver" gives a very shiny finish. "Old/Bright Silver" is best thinned to about a 65/35 ratio with Floquil "Diosol" (Floquil’s thinner) and then airbrushed on in fine mist coats.
   
   Under no circumstances use "Diosol" as a paint-stripper to "strip" off an unsatisfactory NMF finish as the "Diosol" will aggressively "burn" the plastic - I’m speaking from experience here.
   
5. "Old/Bright Silver" is touch-dry in about 1 minute and can then be polished with a soft cloth (I leave it for at least 30 minutes).
   
   Dry "Old Silver" looks like any flat/matt silver paint. Don’t be fooled by the dull appearance as a polish with a soft rag will give it a nice shine.
   
   Do not be surprised if after the first coat you need to clean up your seams before applying the final NMF coat/s.
   
6. To achieve different panel tones, especially with "Old Silver", selected panels can be masked off with Post-it Notes (that’s right the ones you write messages on) and Tamiya masking tape. The remaining panels and areas are then vigorously polished with SnJ "Polishing Powder" dabbed on with the supplied SnJ soft cloth.
   
7. Anti-glare panels and trim colours can be easily applied over "Old/Bright Silver" as it can be masked over - again I suggest using Tamiya masking tape.
   
8. A gloss coat over "Old/Bright Silver" is not needed before decaling, as the painted surface is very smooth from polishing.
   
9. A clear coat to seal paint/decals/weathering is optional. I’m yet to seal a finish and the finish of my NMF models is yet to deteroriate (some are now four years old).

Floquil’s "Silvers" can also be used an undercoat for camouflage schemes as the camouflage paint can be chipped/scrapped off to reveal the "Silver" below - great idea for Japanese WW2 schemes which weathered heavily.

As with most modelling products there is a health and safety consideration. A breathing mask must be worn when using the Floquil "Silvers" and SnJ polishing powder (the finely grained powder is harmful when ingested).