Just treat it as a small fishery GG, usual thing, if fish on top floater and dries, next try buzzers and nymphs. If no movement on top try an intermediate and count down using a small lure and a couple of nymphs. If it takes a long count change to a sinker. If they're right on the bottom - unlikely but possible in May - sinker and lures. Fast sinker and booby or a muddler if all else fails. Black hoppers and buzzers, diawl bachs, hares ears, orange tadpoles orange boobies, dabblers, bibios will see you through.
I'd give Nine Oaks a miss if I were you.
There's a very good and not too well known
coarse fishery near Cilgerran called Cwm Gof.
While you're down you really should try the sewin fishing on the Teifi, the Teifi River Guides and Steffan Jones are both very highly rated if you'd like to receive some tuition, give it a go , you might catch the fish of lifetime.