Definitely go small on SoHo. 22's and some 20's. I have fished 18's and gotten refusals. Switched to 20's and gotten in to fish.
As for Clinch, you can't really tell until they show the predicted outflow on their website. Usually on the bottom of the screen they will give the anticipated cfs. You probably can't get that info until 48 hours or so in advance. Hope this helps.