Evolution states that it only provides one deposit address and this changes every time a deposit is made. Does this mean that tumbling is not possible?
I'm using blockchain.info so it has the option of "tumbling", so do I just go for the normal option?
You still can (and should) tumble your bitcoins before sending them to the market. Just send the coins from the tumbler directly to the current deposit address. If the tumbler tends to send the coins in more than one transaction, send the tumbled coins to a new electrum wallet and then make the deposit using that (over Tor).
Using a new deposit address each time only hinders outside observers. If the Feds seize the server (or are currently running it) they will be able to see all addresses linked to your account.