Just steer for the big white building at Southend, (derelict hotel) you will be crossing the tide in the N Channel but you want the tide with you in the Sound, usual thing is to time your entry to the Sound for low water but it is faster if you are later and get a bit of a flush through. The port hand buoys are a long way out from the Kintyre shore, if continuing to C'town allow about 2 hours.
Hazards, extensive fish farm well out in Glenarm bay, shallow and rocks close to Kintyre until after the Arranman Barrels after that the cliffs are quite steep to until you get to Davaar..
I prefer to start from Belfast Lough and leave Pattersons Rock to port as the tide more than compensates for the extra distance.
There are a couple of moorings off Carradale if you are avoiding the wee toon but can be rolly.
Get a copy of the Clyde Cruising Club Sailing directions, "Firth of Clyde" . It describes this trip and what to take into account. Edition 3 just published this year.