Even tho I did summon Solaire for Gwyn the first time I dont suggest it,its much more satisfying doing it on your own.
With Solaire its basicly you hit over and over while Gwyn pounds the warrior of the sun,nothing intresting to it
I'd agree with that. That's how I did it on my first go. There's nothing more satisfying than seeing Gywn leap at you when you first enter then immediately parry his attack. Guy goes turn in about 3 or 4 parries with Power Within and BKH equipped.