Early Havoc/Bostons were all glass nosed versions, but most had some form of fixed forward facing armament. Usually two to four 0.3 or 0.5in guns. The name was just a country specific thing, it didn't relate to the type of nose.
Apart from the RAAF mods, the RAF also modified some Bostons for night intruder work. First with 12 303s in the nose, then four 20mms in a belly pack. The latter arrangement was copied in the P-70 nightfighter, which were factory conversions of glass nosed A-20s.
The main difference between the G and the earlier models of A-20 was the twin 0.5in rear turret, but it was also the first production aircraft with a solid nose. The RAAF received some A-20Gs from the USAAF and I'll do one of those as a skin later on.
WRT layers, I go paint and markings lowermost, then weathering, then panel lines etc on top. I split the lines into panel line and hatch line layers and make the panel lines more transparent than the hatch lines.
