Ah, thanks for the screen, I see what you're trying to do.
The architecture kits are standardised to assist the developers construct rooms quickly. Where standard components don't fit, Bethesda construct their own custom components to fit (as an International development house does)
This means that you and I have to find a way around things. Which means that our digital vision wil take longer to get to than we first imagined. I opened the creation kit when it first came out last year, fumbled around and gave up. I played the game normally, saw a few items of scenery and started wondering what would happen if I could cut piece X over piece Y.
So., as said, I'm not familiar with the Dwemer kit, but perhaps you can shrink some items to fit, rotate them, lift them from another kit.
I wasn't happy with the stairs available in the Solitude kit, and didn't want everyone recognising the double spiral from the Blue Palace, so I shrunk the Sol Large kit down to fit the Medium kit, and placed it outside the grid (Grid snap off) I've resized columns to edge the sides of certain scenery and used blocks and other blanking scenery to hide the gaps where the netherworld shows through.
I know that it might feel like you're putting a sticking paster over things, but if you look closely enough, you'll see it's how Bethesda themselves do it.
There are plenty of objects available to get a good bit of scenery. The constant select>click>preview?cancel means that the various kits aren't easy to work with, but this is only due to experience.
Have a go and post back with your efforts. I'll let you know what I think.
Best regards
James