is there a good size for merchant fleets? i'm in the process of scrapping my 1-2 merchants and leaving it all as 10 bulk or 10 merchants.. from every single planet.
I just pick a number and build fleets of that size. When I get too many of them I scrap them and merge the fleets. So I started at fleets of 5. Then 10. Then 25. Next will be fleets of 50.
As long as it's inside your territory, I don't think it really matters because it's very unlikely that they'll be attacked. If you're sending outside your territory, then keeping them small is probably best as if they are attacked then you won't lose much.
