Here’s the thing nobody tells you before you open six browser tabs: these tours are not competing versions of the same trip. They’re two completely different trips with similar names. The short answer: If you want Loch Ness itself, book the Loch Ness, Glencoe & Scottish Highlands Tour (12.5 hours). If you want the Glenfinnan Viaduct — the Harry Potter bridge — book the Hairy Coo Glenfinnan, Glencoe & Highlands Tour (12 hours). You cannot do both in one day, even though the listing photos may suggest otherwise. Everything below explains how I’d choose between them, and what the other four…