Germany only built 20 tanks because Ludendorff was too short sighted to see how important they’d become. The Germany player might decide to give priority to tank production; why should he be limited to Ludendorff’s blinkered view?
The Allies probably had as many shock-trained troops as the CPs, why does it matter what organization they were in, at this scale? And again, the Allied players may decide to give them a higher priority than historically, perhaps in response to German tank developments. As long as it can be demonstrated that they had the capability to put the unit in the field, the player must decide for him/herself how many to produce. Or do you suggest that players MUST produce every single unit in historically correct proportions to each other?
Turkey did not, COULD NOT build tanks or anything else other than basic infantry equipment. They got supplies, in fact they got pretty much everything, from their allies, but every single rivet of it had to be physically transported either by sea or by rail to Turkey. These were not in kit form, but fully assembled mechanical units, right up to battleships and bombers.
This is why the Allies decided to attack the straits; they were vital for CP supplies to Turkey, and for Allied supplies to Russia.
As I said, by all means allow Turkey to convert units built in Europe to their own units in exactly the manner of the Goeben and Breslau. You can have as many Turkish tanks as you like as long as the German and Austrian players are prepared to supply them.
Allied shock troops and Turkish controlled tanks were in the war. However small the numbers historically, it should be up to the players to decide how many they want to pay for. Otherwise, where’s the game?