Hardly a waste. 1b for a large plunder increase. Waste of time to try and save 25b when it will take you a while for a similar increase. Youre wasting if youre building a T4 instead that youre just going to knock down.
You don't need to save up enough gold to go to level 2 colony right away. Level 1 is a pretty significant jump in stats. Once 25 billion doesn't seem like much, go ahead and swap out all level 1 colony.
If you war with a bunch of lvl1 t5's you will be disappointed. I built t4's til land complete. Then convert.
Build first 4 highlands with t4, convert lowlands one by one to t4 and then start buying t5 level 2s to 37 lands. Convert your first four lands to t5l2 and then keep buying lands until they cost 120bil i think, somewhere around there
-Senorita-'s advice is the best. By building guilds on highlands, you're saving yourself time, and getting considerably more gold. If you built T5's right away, you'd probably be overwhelmed by the speed at which you get money… Building T4's is always an option, not the best though.