I’ve had one for a while now and built another towards the end of last season Having proven the concept with the first one. There are a few LL with Flow Frames now. There are lots of LL videos and photos now, have a look through as many as you can to work out what features you’d like to incorporate in yours. I can not recommend enough modifying the basic design to accept cover boards above the frames and below the roof.
This is a link showing mine Long Lang with Flow Frames
I like them a lot. Good luck building yours.