No experience of Capel, but I’ve done Kilbo several times. I’ve approached from both Prosen and Clova, and it’s definitely a quicker ride/more accessible from Clova. Park in the Glen Doll carpark, ride up to Corrie Fee, climb the corrie backwall enjoying the cracking views, have a bite to eat on top of Mayar with a smashing view, fire across and top Driesh if you can be bothered, then blast down Kilbo. As has been mentioned, techy while you follow of the side of the Shank of Drumfollow, but so, so satisfying when you nail it. Ride through the forest at the bottom is brilliant. By far my favourite natural ride so far!
FYI it’s about a 2 hour ride if you don’t stop, 2.5hr if you enjoy the view from the top Strava link