Hi Cheekykid,
Your at the stage I am at. Was trying to leak test my kit last night until the pump started leaking, realised I had missed putting the O-ring in it DOH!! Your also using the same case as me

and yes its a good choice. I am also a first time watercooling noob lol. Now I havn't chosen a kit gone custom but I still assume you have to cut up all the tubing? So the best thing to do and what I am doing is to fit the CPU and GPU (if you have a GPU that is) and then get all the tubing and positioning of the reservoir sorted etc. Then just take the blocks of and put a towel on the center divider of ** case and put the blocks on that. Remove everything from your case apart from the watercooling stuff and then hotwire a PSU. Then just fill ** loop and test for 24hrs that way nothing is going to get damaged if there is a leak. Then when you know the loop is leak free just install everything into the case that way you don't have to empty the loop either just screw the blocks to ** mobo and graphics card.
If that made no sense let me know will take some pictures of how I did it.