I have now reworked it and put the new version into the latest beta patch. Download it and test it out...
Colonising before the mid 16th century is harsh now, until you've get enough colonies going.
1) There's a minor penalty depending on the production efficiency, and then a minor bonus when it goes over a certain limit. (>30%) (Range on modification is -3 to +7%)
2) For the first two hundred years there is a penalty which is decreased by 1 each eight years. Its at 25 in 1419. (This is not valid if the province already have a colony OR a tradingpost. Its only for the first establishment in the province.)
3) For provinces which is not adjacent to the same landarea as your capital, you are now limited by your monarchs ADM value.
The game counts every colony not yet a colonial city into a value,. and then substract the ADM value of the monarch. Each colony above the ADM gives a 5% penalty to colonial success.
4) During the first twenty attempts at placing a colonist you have a penalty which decreases by 1 each time. (It starts at 20 and goes down to 0.)
5) A small bonuses have been added for placing colonies adjacent to owned provinces. (+5%)
Trading posts are not affected as much as they are so easily destroyed in a war, but the following 2 effects have been added.
1) For the first eighty years there is a penalty which is decreased by 1 each eight years. Its at 10 in 1419. (This is not valid if the province already have a tradingpost. Its only for the first establishment in the province.)
2) There is a penalty on 5% if you have more tradingposts than cities in your nation.