Hi, welcome to the forum. Yeah, I think you've got 2 really nice demos there with lots of potential. They've both got good dynamics - they build and break down nicely. Structurally they felt pretty good to me already... the intro on the second one in particular was pretty catchy. I suppose the 'conventional' place for intro hooks to repeat is coming out of a chorus - have you tried that, if you want to reintroduce it? I also liked the outro on the first one a lot. Anyway it'll be great to hear these with lyrics once you have added them. Based on current draft though I'd say don't worry too much about structure at this stage... It's sounding good and the length is good too.