Don’t paint over acrylic with enamel or vice-versa. The solvents in the enamel can “craze” the acrylic. I speak from experience.,…..:apologetic:

Great work, have two 1:72’s in my stash. mk 1 will be Bob Stanford Tuck’s and a Va of Douglas Bader

Is it possible to visit the facility?
Great pictures

Could it be to minimize lift and make sure that the aircraft stays on the runway?

I also use Tamiya tape, works well. If the surface is a bit uneven and there is a chance of seepage I give it a (very) light pass with the airbrush using either the colour which is to be masked or a varnish(matt/matt-satin/gloss), As for the decals you could try these guys:

http://www.aviationmegastore.com/

They have a huge decal collection.

Good luck with the kit.