Probably not feasible since you're away too long, certainly you wouldn't want him pooping in them!
Peeing is usually a sign of frustration or asserting dominance ("this is mine!"). It seems to me that Gizzy is constantly jealous of Forest or maybe trying to dominate him by peeing on his spots where his scent is, even tho he hasn't used that bed for a while. So does Gizzy end up takie over these places? And has he peed on Forest's new resting place? I guess the important thing here is, does this bother
Forest or could he care less as he has a new "hammock" recliner. At one time you said that Forest was dominant over Gizzy, so has their relationship flipped? Does Forest still dominate Gizzy or does he pretty much ignore him and do his own thing? If Forest is still trying to dominate Gizzy it could be Gizzy getting back at him by peeing on his bed.
I've had stud cats, unspayed females, as well as neuters and spays. It's been my experience that generally speaking males, whether neutered or not, tend to spray a lot more females (unless they're in heat!). Once a male even tho neutered starts spraying regularly
, it's very difficult to correct this behaviour, as often events will just set him off---change in household (new person/another pet), change in routine of owner (shift work), seeing another cat outiside, smelling another cat off your hands or clothes. Any of these things and more could be a trigger to spray something. It's natural for whole male cats to spray, but I have known some breeders who were able to let their stud full freedom in the house and never sprayed. So it really depends a lot on the cat's personality and whether he's bothered by things or just really laid back. I've had some neuters that did spray and others that didn't. My present neuter has never sprayed and he has neighbour cats regularly visit and look at him through our patio doors. You might just have to reconcile yourself that Gizzy is a spayer
, at least from time to time, and try to discover what it is that triggers it so it becomes a rare event, but have a good urine eraser just in case.
If Gizzy's just spraying while you're out, perhaps the only solution is to keep them separated; let Forest have your bedroom or let Gizzy have the bathroom or get a dog crate and keep Gizzy confined until you get home.
this is so long, I got carried away!