Go for the Tygon, 1/2 ID. You've got a very nice block, possibly the best one, and its hidden little secret is that it works better with 1/2 tubing.
I'd advise for the bigger Eheim, but since you're not into overclocking, then the 1048 will serve you well.
I really can't criticize your choice not to overclock, because it's up to you. You established the goal for watercooling, and that's a good step: some people get in it without a goal, and guess what, they're still tweaking their system, a couple of years later. Congratulations for sticking to your guns.
You'll get a long life out of your system.