For short term speculations, you should go with those that has a lot of volume. Because if you're going to do the strategy of others of hunting potential altcoins that haven't pumped yet, it may take you a while. Whilst for doing such trade with high volume coins or tokens, you won't need any waiting game for them. I'd always advise to go with Ethereum, no doubt whether you're going to be long on it or short, you've got no problems with it as it's flexible as usual.