Top Thrill Dragster. Magnum is a little too rough for a 24-hour marathon.
Would you rather all the Cedar Fair parks demolished, or all the Six Flags parks demolished?
Those glitches happen because you used wall pieces. The base blocks will look exactly the same since the majority of the block will be inside the building and out of view, except it won't glitch and it's much easier to build buildings with. (Especially the quarter blocks)