Use Webro WF100 or Triax TX100 or Labgear PF100 and you won't have any issues at all. These are good all-copper cables.
Personally I use WF100 for all my install work, but that's because I buy it in 250 reels. If you're looking for shorter lengths then there are resellers on Ebay that do the twin "shotgun" version of this. Just make sure that it is genuine WF100: Check the pictures because WF100 has the outer jacket marked with "Webro WF100" along with the length marked in metres.
WF100 is an RG6-sized cable. It's roughly a 7mm diameter. RG stands for Radio Guide and it's a set of specifications that list out physical dimensions and the impedance of the cable. What it doesn't specified is the materials for the construction. So, RG6 is a shielded 75 Ohm coax, but there's nothing in the basic spec to say how good or poor the shielding is, or what it is made from, or what metal has been used for the centre conductor. That leaves a lot of scope for very different levels of performance.
Sky Q will be perfectly fine with WF100 too. It's better than the cable spec that Sky are currently using. The only thing to add is that the installers putting in Sky Q are fussy about cable with joints or that goes via wall plates or other intermediary devices such as distribution amps.