I've done a bit of modified Czech type nymphing.
Similar but generally using smaller flies....coarse fish in the Uk don't tend to hang out in the same, super fast water, as grayling so you need less weight. The swims are often deeper though so you need more weight!
I'll usually make sure the point fly is a small relatively light weight nymph/spider, this catches most of the fish, the other flies are just to get the little fly into the right zone, but do pick up odd fish.
It works best in the hottest weather and also if the venue is a little coloured. I've fished swims that never produce to the method but get the right tinge and suddenly it's a fish a chuck...for 7/8 fish anyway.

On the dangle with a heavy fly(very heavy at times) on the dropper and a spider on the point can be the best method (only method) at certain times...I've had loads of fish like this....experiment and learn what works for each swim, or even part of a swim...let alone venue!
Dee
P.S paul where/how did you get your flattie? If you start getting a few I'll want you to guide me to one!