Just a couple of points, in case anybody might be curious. The Canadian tech tree looks amazing, particularly the political choices, very realistic and generally overall a good tree, true to the development of the Canadian war effort. I am a private researcher focusing on Commonwealth arms and armament (in general, I am more focusing on ground equipment but I dabble in air power too.)
A couple of things I might want to add.
Canada's armored and vehicular focus, and production. Canada produced over 1900 Valentine tanks (sources vary slightly but most hover around 1900-1950) and, in addition, we produced huge numbers of
"RAM-I and RAM-II" tanks as well as
"Sexton" SPGs, comparatively for a country of our size. The lack of reference of Montreal Locomotive Works in the tank line is a little disheartening. I'd also be curious as to why the RAM-II wasn't actually added in the same way the Sentinel programme is made reference in the Aussie tree. (Both were essentially developments of the Lee chassis, more or less, the Sentinel, certainly more so). Not exactly sure how you'd work them in as a development. Much less well is known about Canada's intense foray into Armored Car development, including the very impressive 8 wheel
Wolf which featured in it's initial stage, 3 engines, 8 wheel drive, a 60 inch turret ring and the turret taken wholesale from the RAM-I (production versions would feature the later RAM-II turret complete with 6 Pounder)
In addition, I would be interested to see perhaps something to do with Canada's indigenous development into SPAA, the
3.7" RAM and the
Skink SPAA are both interesting options, the later was actually approved for service and production by UK but only canceled due to factors involved in the 'real' war (mostly the German airforce not existing in any capacity.).
General Andrew McNaughton was another huge source of Canadian tech development, he was the head of the
National Research Counsel, and a leading expert on artillery, but due to his experience in the civilian world as an all-round engineer, also took great interest in flame warfare, tunneling and mining, mine clearance, airbursting, anti-aircraft and various other artillery techniques, all of which he had a hand in. He was involved in a number of "secret" development projects in Canada- and the long and short of it was that other than being a mediocre military leader and general he was a bit of a mad scientist and dabbled in everything from Artillery fire control and gunnery systems to hyper velocity weapons development- and it appears from my research into the UK and Canadian archives that he was really one of the big pushes into tungsten core'd projectiles, an early believer in
APDS and APCR weapons and he pressed for more powerful tank guns. Much of this research was done at
Valcartier, at what would eventually turn into the
CARDE (Canadian Armament Research and Development Establishment) postwar. After the war, Canada's lead role in hyper velocity and APDS research would have them on the cutting edge of
hypervelocity projects far into the 1960s, developing equipment for the UK and Commonwealth forces.
In Canada, we had developed a number of prototype weapons, including the
"David gun" (essentially a wildcat gun, taking the 2 Pounder Projectile and the 6 Pounder casing) and the
"Canuck Gun" which was, for all intents and purposes a "longer 6 Pounder" that had higher performance, neither of which reached production due to the rapid pace of the war. We were also leading developers of the "Pot-Type" sabot, which in the intern fixed a great deal of the accuracy problems of the inaccurate ww2 era Sabot ammo.
Another "missing" outlier may be
Canada's tungsten production. Canada had a massive tungsten production and supplied herself and the UK with such a mass of Tungsten that reports I have compiled from mid '44 state that Canada should "cease increasing production due to a lack of processing facilities", meaning that we were producing such a mass of tungsten that ourselves and the UK could not actually turn the raw material into usable material quick enough.
I've got a lot more suggestions so I might comment again later!