[pellelu]

Actually, I'm using a separate reservoir with a D5 but I recently purchase one of the new reservoir by Koolance RP-452X2 Rev 2.0 Dual 5.25 Reservoir f/ 1 or 2 D5 Pumps RP-452X2 Rev 2.0 Dual 5.25 Reservoir f/ 1 or 2 D5 Pumps [RP-452X2] - $139.99 : DazMode, The Best Canadian PC Watercooling and Modding Store!. You can save a LOT of space with a good pump/reservoir combo. I will be able to run a second loop AND gain space in my case.
For your fittings, you can use these : COMPRESSION FITTINGS 7/16 - 5/8 : DazMode, The Best Canadian PC Watercooling and Modding Store!