1. Of course you can cut tubing to the right size, you can use scissors, shears, a sharp knife, anything capable of cutting through plastic basically.
2. That card looks like it has a custom PCB so a standard 670 waterblock will probably not fit it. A good place to start for questions like this is the 'EK cooling configurator' (google for it).
3. Have you read the stickies in the watercooling section? They provide an excellent beginners guide and should answer most questions you might have. The important thing is not to rush into watercooling without doing the proper research. Otherwise you will probably end up spending a lot of money on sub-optimal or incompatible parts.