I have a densely planted 120H with two 600's ( 2075 and 2275 to be exact in older Eheim nomenclature ), lily pipes, inline heater, UV sterilizer, etc. and think the flow is just right. I like two filters versus one for various reasons versus one monster filter. Although I would have an ADA Superjet ES-2400 if I had the budget for it, lol.
I bought an Eheim 2074 years ago to be the sole filter on a 75 gallon and never felt like it provided enough movement. After a few months I replaced it with a 2076 and still didn't feel like it was enough and finally added a 2075 to go with it. I'm not interested in a raging maelstrom, but want a gentle yet, let's call it thorough, flow in the tank.