ok so i did the math for tungstin and there is 792 tungstin in game for 49.5 tonnes produced per year during ww2. 792/49.5=16 so we have our conversion rate of x16 for in game representation. so for copper i came up with 91.2 tonnes produced per year during ww2 so 91.2x16=1459.2 We sould better distribute it it based on location so:
USA 32.4x16=518.4
USSR 4x16=64
Canada 10.2x16=163.2
Rhodesia 10.6x16=169.6
R. Brit Empire 4x16=64
Greater Germany 1.3x16=20.8
Norway 0.9x16=14.4
Sweden 0.3x16=4.8
YugoSlavia 1.7x16=27.2
Japan 4x16=64
Latin America 21.8x16=348.8
Findland is not on here because when i did some research they combined its numbers with USSR due to the mine changing hands during the war. I recommend rounding up with all number and even then there still gona be a little area for flexability in exactly what regions to palce the copper and in the case of "Rest of British Empire" and Latin America you have flexability on where to place that copper. as you can see some countrys will be getting most of ther copper via trade. weither its from a neutral Latin American country, a war ally or by taking it from a neighbor.

Thanks, that's a useful resource, but it's worth considering that my main concern is game balance and delivering the experience that the mod promises, rather than historical accuracy. I'm very, very cautious about increasing resource abundance because that might reduce the importance of controlling map resources, and eliminate invasion motives such as Barbarossa.

My method for balancing this has been running through matches up to '40 and counting global army sizes for major, minor, and minie nations. I can use this to breakdown how much equipment is being produced each year, and get an estimate of how much resources are needed each year, which is what I did for Grain and Copper. With Copper, I'm happy to increase that number a little since copper shortages in WW2 were not decisive. Grain, however, needs to be truly sought-after, in my opinion.

A suggestion so you can achieve both would be to increase the amount of equipment needed for units. I would match the units manpower with equiment so for a 1000 man unit you would need 1000 of infantry equipment and however much ammunition. Just make ammunition and equipment have a lower production cost.

Could also add national focuses or laws that change as your navy and airforce grows that decreases production of ammunitions and gasoline to simulate their uses, since I dont think they use equipment. And you could remove the oil requirment to build the ships.

What you're suggesting is the same thing as simply increasing the production cost of rations. Again, all this would do is increase the amount of grain needed for every country in the game, not just Germany and Britain. The bottom line is the same: Germany needs about 5 factories on rations at the start of the war for their armies.

I could add a few wheat deposits to Germany, Britain, etc. if they were so small that they made almost zero impact on production (like 1 or 2 wheat units). It'd be very token-ish, though, and would still slightly decrease the impact of shortages on Germany (it's already possible for Germany to be well-stocked on Grain if the imports fall in the right way). But I'll keep it in mind, since it's clear that lots of people find the Grain distribution to be very odd.

The Heart of Iron game is based on accuracy first then balance second, this is why Germany starts with a massive industrial capability that its surrounding neighbors lack behind in (minus France thats another issue). what im suggesting is you make copper and wheat production match or near match what is historically accurate then adjust the consumtion rate to allow for whats balanced.

for example if you did increase the grain by x12 then you could increase its consumption rate and factory requirements. such as instead of taking 8 grain to make a rations it now takes 96 per factory. you could literally give Germany 100 grain and it will look like a lot but in reality its only enough for 1 factory. then countrys like USA and Agentia should have massive reserves like 1200

my prevous comment leaves the problem of trading for resources becomes inpractcle, this leave 2 things to address. wheat trade per civilian factory need to be adjusted (never seen a mod do this, so dunno if its possible) and the fact that you can actually use the disbalance in wheat trade per civilian factory to balance out the mod. it would have to be scaled in order to work properly such as if ration producion toke 24 wheat to produce, then it would take 3 civilian factorys to get enough wheat to get enough wheat to produce 1 ration. ie, if Germany started with 100 wheat, it could produce 4 rations on its own with trade needed for the last 1, it would need 3 civilian factorys to get enough wheat for this 1 ration so it balances out in this manner

If you add more copper to teh game you can easly help balance it out by making Motorized, Mechanized, Tanks, Planes and Ships cost a small amount of copper to represent the eletronic wiring in them.

I think that in my experience as eg Germany there should be a farm building like the synth rubber and oil to make food

The grain bases should be doubled and the ration should require between 1 to 3 grains to make not 8, if there aren't almost any nation to trade grain be harshes as it is, imagine with the new nations of Man at Guns DLC