There is an interesting trick especially usefull in Proportions:
First, remember that population in Proportions is very "heavy" and reproduce 10 times slower. Starliners and colony ships move just 1 pop. unit for example. Thus, when you create a colony, it has 1 population. 10 turns later it will have 2 population due to the way SEIV assign pop. an integer value. It should be 1.1 but its rounded up to 2. Now, suppose you have another race. It is very usefull to mix them up - if you have 1, for example human and 1 Phong, every 10 turns you will get a new human and new phong !
Compare situations when 1) you have human planet with 2 humans and phong planet with 2 phongs - next year you have 3 humans and 3 phongs. 2) you mix them up - 2 planets each with 1 human and 1 phong. Next turn you have planets with 2 humans and 2 phongs
- double population growth !!!
It is almost cheating I think, and is just another reason beside helping AI why I scaled up population 10 times in my Proportions games !