New fear unlocked regarding the gutters...
Clearly, the math is not strong in this one.
19 mm (added fascia board)
+ 1 mm (metal cover / drip edge)
+ 35 mm (extended gutter brackets)
+ 5 mm (wider gutters)
= ...NOT 55 mm, which I rounded down to 5 cm for convenience and ease of measuring.
How the hell did I manage this... :banghead:
Did some more practical tests today. For one, the rain - if just a drizzle - just falls straight down off the roof, and won't hit the gutters at all. So that needs some more pondering.
Secondly, the row of added fascia boards should have been 1 cm further down to compensate for the total of the extended gutters.
So I will do a practical test with a plastic lid or something to simulate how the snow will (read: MAY) behave. If that test gives me any reason for concern, I will have to redo the whole row of boards. This is one of the 7 added, carefully measured and leveled, boards.
EDIT:
CRISIS MAY BE AVERTED!!!
I could not get rest in my soul about it, so I checked some earlier photos for a rough measurement, and was just outside to lean a piece of the new gutters between the highest bracket and the railing on my custom scaffolding, holding it about where it would be.
Then I tried to slide a plastic lid off the roof, pretending it was a chungus load of snow...and it wanted to sail above and over the edge of the gutter every time.
So I am taking my chances on this one, and leaving everything as is.