but I'm not really sure about flow rates. I want to make sure it's enough for my CPU-370 block, my GPU block, the fusion thermo block on the Maximus V, and the two radiators I'm housing. But I don't want it to create so much flow pressure where I have to worry about forced leaks and built-up pressure.
What can you guys tell me about the flow rate of this pump vs my setup?
There is flow rate, and head pressure. The more restriction you have in your loop the higher head pressure you need. The MCP35X is a strong pump with nice flow and even better head pressure, but don't take my word; research it. Always research before you buy.
Some good places are http://martinsliquidlab.org/
Both of those sights can be found in the sticky at the top of the forum. If you havn't read it you should, it has lots of useful links and info on the exact question you are asking and everything else involved with watercooling.