When I leave Sergio for up to 8 hours while I'm at work, he is much less stressed when I leave his crate (door open) in a smaller x-pen area, with food, water, blanket, toys, and potty pads. He also likes to play with a fuzzy pair of my socks, and I'll leave one of my slept in tee shirts.
An ex-pen is much less confining than a crate, and you have given him a potty spot. I was concerned for the original poster because I thought her dog was crated for a full work day... it turns out that he's only crated for about 4 hours, so that's fine for an adult dog.
When I have to run an errand and I'm just out for around an hour or less, I let him have free run of the apartment, and he doesn't have any accidents. However, I don't think he's less stressed than he is in his crate or a smaller xpen area.
If a dog is properly introduced to a crate and ex-pen, it SHOULDN'T cause anxiety. It should feel like his "safe place". Kodi often chooses to nap in his crate even when we are home and the door is wide open. It sounds like Sergio feels the same way. We have found that Kodi is LESS happy if he is free in the house when we are gone. He just wanders unhappily until he eventually settles into his crate on his own. I don't think he would get into any trouble loose in the house. He is well potty trained, and past the chewing stage. But you never know. When he is in his ex-pen, he feels secure, and I
feel secure that he won't get hurt while we are out of the house.
Also, I know that some Hav owners feel that Havs should only be with stay at home parents or retired people, but I don't feel guilty leaving him for the day while I go to work. He does best as the only dog in the home, and he doesn't fuss or bark in the morning. We just needed to establish a routine.
You are right. Not every Hav can adjust to being home alone all day, but some definitely can and do. You are right, that establishing a routine, and making sure you give him lots of attention when you ARE home goes a long way toward helping him adjust to being a "stay-at-home Hav"
While I have the luxury of working out of my house, so that Kodi is rarely alone more than 4 hours or so at a stretch, I have to honestly say, that I think he is also the type of Hav who COULD adjust to being alone during the work day. He really spends a LOT of his day sleeping in his crate (without a door on it) in my office anyway!
I have found that with Sergio at least, the more I let him start lounging on my bed, carpet, sofa, etc., the more I think he viewed those spaces as "his den" where he doesn't want to go potty.
I think you may be right. Kodi is trustworthy anywhere in the house now, but he was reliable in the kitchen and family room, where the family (and he) spends the majority of time, LONG before he was trustworthy elsewhere in the house. The place we had to watch for the longest was the dining room, perhaps because it is only used by any of us on an intermittent basis.