Typically, if you don't like the Altitude fit then you will like the Lapponia. They have two very different toe boxes with the Altitude being narrower and the Lapponia being more standard width for us. Really the main difference between the Lapponia and Nevada would be stiffness, and the Nevada...
The Crispi Altitudes and the Briksdal family of boots are typically our best fitting boots for a narrower foot. I wear the Briksdal MTN and MTN SF for all my hunting and I also have a narrow foot.
I would check out the Shimek. It is a 400 Gram insulated boot that is a 2 flex. It is very similar to our Lapponia series boots just insulated. The other option would be the Wild rock at 400g insulation and a 3 flex it won't be too stiff for the short walk and long sits.