Triumph Bonneville DIY Air injection and Airbox Removal

So I know that airbox removal has been pretty much beaten to death (at least by the Triumph community) but as I managed to save quite a bit of money doing this myself (not with a kit) I figured I'd document it. This modification replaces the stock airbox with individual air filters clamped onto each carburetor intake. The airbox snorkel and internal baffle restrict the flow of air into the carburetors; by removing the maze of plastic, we free the carburetors to draw in more air resulting in a modest performance increase. I'm going to skim through the steps that are explained elsewhere and focus on the parts that involve a little creativity and ingenuity.

For starters, airbox elimination consists of a few distinct parts. In no particular order (click the link for a detailed walkthrough):

the stock airbox has to be chopped to make room for the new air filters;
the carburetors have to be re-tuned to adjust for the increased airflow;
the secondary air injection system should be removed;
the carbs have to be braced against the frame;
the new filters need to be installed;
the crankcase breather hose must be re-routed and fitted with its own filter.

Finally, the carburetors need to be balanced and and adjusted until everything is running up to spec.

Instead of compiling one monolithic article, I've broken these down into a few self contained posts to keep things relevant.

Parts
Airbox mods:
2 K&N RC-1920 air filters (54mm I.D.)
1 stock airbox
heavy-duty velcro

AI removal:

2 M12x1.25 drain plugs
2 M12 crush washers

crankcase breather:
1 K&N 62-1015 crankcase breather filter

2 1/2" hose clamps

15/32" PCV hose

For carb tuning:
main jets, pilot jets, needle shims