How much of each good/era would you advice of having
"Asap" in this context means as soon as you have enough to complete LMA tech tree
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If you're uncertain about if you can trade, make a pillow of 500 each LMA, it should be enough for negotiating 2 full GE, if I'm not mistaken.
You'll struggle a bit after moving due to lack of troops and/or goods, but increased city space will allow you to produce more goods, speeding you up in the long run. Duration of this "bit" depends on how many goods you're producing. Grenadiers are pretty far in the tech tree, so you'll probably be up and running even before teching to there. You'll be negotiating GBG anyway, and GE you can fight with grenadiers you get from GE and GBG if you're careful enough. Or negotiate it, at this point it's simpler.