The H70 is an asetek unit, meaning you can take the stock mounting bracket, the intel one i believe, and just drill holes in the feet to match your card's holes. Then get some screws from the hardware store that are long enough, and a shim (you'll need a shim if you go with water cooling anyways, and it's only $1) and try your h70 out.
I kinda feel a waterblock is just overkill, when a clc will keep a 7950 under 60C anyways. However, custom loops are far superior if you are doing multiple cards (you can do 2x closed loops, it gets a little crowded, but 3 is where it's hard to fit) and there is an aesthetic to them as well. You also need to keep the VRM cool, so make sure to put VRM sinks and a fan if you go the closed loop route. Or the custom block, for that matter, unless you use a full block which are a lot more expensive.
Also the %50 power limit fix seems hard and I don't want to mess with my registries plus I've never seen any throttling on my card.
It's really not hard to do, the instructions are pretty simple. It's necessary to edit registries all the time for various tweaks to your computer, stuff as simple as how long to menus take to slide out and stuff. The guide also shows you how to save your old registry, so worst case scenario you just pull back your old registry.
There IS throttling to your card, you just don't notice it. You can only tell when you compare if you put the power limit on, then off.
But here, run a stress test like OCCT. Pull up HWInfo, and look at your clock rate and utlilization. Your card won't sit flat at 1ghz or whatever the clock is, it'll constnatly go to 500mhz and ~900mhz. This is throttling. A card that isn't throttling will run it's max clock 100% of the time, and run at 99-100% utilization 100% of the time. I guarantee your card is heavily throttled and your fps is half of what it should be.
Not doing the power limit fix, is just waste of money, you might as well have bought a 7850. This is something that's true of ALL higher end AMD cards, ie the rx290x and 7990 also have these 'issues'.