I've researched about H8K2's defensive gun a bit, I update it.
All 20mm cannons on the H8K2 were Type 99 Mark II, were supplied by drum magazines. One drum magazine includes 45 20mm shells.
The H8K2 Emily mainly had the following defensive guns:
Front - 20mm cannon x1
Top - 20mm cannon x1
Side (Left) - 20mm cannon x1
Side (Right) - 20mm cannon x1
Tail - 20mm cannon x1
Front turret:
I have the drawing - but it is old 7.7mm turret's one.
it shows there were 7 drums.
But, my another Japanese H8K2 book claims that front 20mm turret was 225 rounds.
so it should be 45 x 5 drums = 225 rounds.
Top turret:
I have the drawing - top turret had 10 drum magazines.
so it should be 45 x 10 drums = 450 rounds.
Side turrets:
I have the drawing - but it is old 7.7mm turret's one.
it shows there were 7 drums in each.
no claims in my another book, but remember the front turret.
It seems 20mm drums were reduced to 5 from 7 when upgrading turret from 7.7mm MG.
so it's maybe 45 x 5 drums = 225 rounds in each turret.
Tail turret:
I have the drawing - tail turret had about 10 drum magazines.
I think it is the same as Top turret's one.
so it should be 45 x 10 drums = 450 rounds.
Researching is still continued, but I believe it's good information when modelling Emily. I can scan these drawings.
Thanks.