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I assume the 'markers' you're referring to are the ones pointed out in the image. As far as I'm aware, the new player locations are fixed and created at the start of a world and not during the game. I'll check tomorrow, but I'm pretty sure this is the case. I also assume you're referring to Firestorm 10 and the Camp 12 in the diagram is where you want to place your base. You have not indicated the reservation so anyone in your alliance or any other could take it once the new player locations are used.
Also, given that your base is a level 10, and still on the edge of the world, you will have a long time to go before you can drop your 2nd base would be my guess.