Wild Chrome

I think that in any type of fishing fly or otherwise you set your drag where you wantit and never touch it. You especially never touch your drag when you have a fish on unless you have an emergency ie. drag is so tight the fish can't run or so loose you cant reel when the fish isn't pulling.
If a fish "goes over" on you you either have to chase them or hold them tight or give them a little slack and hope they come back up. My preferennce is to chase them. However if I can't chase them there is only one thing you can do, point your rod straight at the fish and hold the spool, the fish will either turn,break off or bend the hook out. Assuming you couldn't follow the fish down river I'd say you did everything you could and the simple reality is you can't land them all.
If you feel like you weren't putting that much pressure on the fish then you might want to examine your hooks..