Steve, we got there about 12ish grabbed some food then rode from about 1pm, took about 4hrs to do the W2, whites and the wall route, it was still light till about 6 well biking light.
Would recommend doing the penhydd route as thats a great descent once you get to the top. The trails are a typical welsh trail center climb for what feels like ages then a great downhill. The whites on its own i can do the climb in under an hour and the descent 20mins, and im not exactly the quickest! took us longer to do the W2 as tbh my legs were tried that wall climb took it out of me a bit!
Comparing it to the Twrch im not sure as ive never rode that.
Other than that check out the website as they are doing some trail work over the next few weeks,