OK, Feedback from a game I converted as UK. The situation in 1819;
I had colonised around 75% of the provinces in North America, having ejected everyone else from the continent. About half of the Carribean and a chunk of Brazil was mine too. Bits and peices in Africa, a significant foothold in India, various things in the East Indies, all of Australia and New Zealand. At home, I had the whole British Isles plus all the Channel provinces of France.
My nemesis in the game was AI France. They'd diplo-annexed Austria and Hungary in the 16th century and basically dominated Europe. To make matters worse, they shrugged off their BB to ally with Spain (all of Iberia except Lisbon, Mexico, Venezuala and Chile, bits of the Carribean), The Papal States (owned everything in Italy which wasn't French anyway) and Poland (a fairly thin stretch of territory running from Pommerania to the Black Sea). Sweden was the only other real power in Europe, with all of Scandinavia, much of central Germany, and large tracts of Western Russia.
I tried converting the game both with and without POP conversion. Country: converted population (millions)/basic population (millions);
China: 275/362 (good enough)
France: 219/88 (massively overrated by converter)
Ottoman: 158/53.4 (massively overrated by converter)
Japan: 113/27.4 (massively overrated by converter)
Spain: 99/33.4 (massively overrated by converter)
UK: 86.6/74.8
Indore (Delhi): 62.7/62 (Incredible. India is apparently fine)
Sokoto: 49.5/8.4 (massively overrated by converter)
Papal States: 39.4/7.2 (massively overrated by converter)
Egypt: 21.5/3.3 (massively overrated by converter)
Flanders: 13.2/1.9 (massively overrated by converter)
Korea, Khiva and Burma were all substantially underrated by the converter.
Here's my suggestion, for saves starting at 1419;
Provinces in Europe excluding Russia, Asia Minor: divide population by 2
Provinces in North America: multiply population by 2
Provinces in Japan and Africa: divide population by 3
Provinces in China, Korea and Indochina: multiply population by 1.25?
Navy and army conversion seemed fine. Could you change the code so that the unit names are capitalised (i.e., not "infantry division" but "Infantry Division"). Also since that's in English it'd be reasonable to have "1st" rather than "1." I realise that "1." is the standard form in a lot of languages, but not in English.
Unfortunately, the vastly bloated French population made them totally unstoppable. They declared war on me within a year of game start and swamped me with their 70 (!!!) starting divisions. I only had around 20 on hand in France.
The independence events happened- but I detected a bug. The event for Para to secede increases the militancy of the cultural majority for the entire COUNTRY- not just the state. Hence I had irate peasants in Tunbridge Wells taking up arms in anger at my domestic policy in Brazil.
Further, whilst perhaps +9 militancy is justified, the existing revolt events have a later event to reduce militancy somewhat later. So for example you could have an event after four or five years which reduced militancy in the state by 3-5 points, making holding on to these areas a much more viable option.
How exactly does the manufactury conversion work? I ended up with only having manufacturies in Great Britain- not even any in Ireland. I had dozens of manufacturies outside the home island.