Behaviour question and Cage ideas

[Fracture]

I recently got my first ferrets! 2 jills, Peaches (5 months old) and Belinda (6 months old) . I got Belinda a few weeks ago and I have had no issues with her

behaviour question 

Peaches we only got about week ago now, when we pick her up she seemed quite friendly a little bit nippier then Belinda. now she tries to nip me when I try to touch her and recently nipped me for putting her water bowl in. She was leaning out the cage drink from it so I slowly put the bowl in as my hand went in to the cage she started sniffing my hand a lot and suddenly nipped me! I tried to scruff her and put her in time out but that seemed to scare her so she nipped me again. After that I just left her and have put a water bottle on her cage so I don’t need to put my hand in the cage. Now when I sit in front of her cage after giving her, her food (whole mouse) she will climb on the bars and hiss at me. I have taken her to a play area once and she had no issue climbing on my lap or other my feet, she was wary of me specially when I moved. Any advice what I should do to bond with her? My only play area at the moment needs me to pick her up. They both live outdoors at the moment so it is difficult for me to sit with them 

Cage question 

Both of my ferrets live outside at the moment but I would really like to move them indoors into my bedroom. I am going to try to do 4 hours play time minimum, but that seems very little time to me and I now there will occasional be times I won’t be able to take them out for that long. So I want something bigger then a double ferret nation. I do have a 3 by 7 ft about space on my floor that I can put I permanent pen for them. There is a wall along the the one side of the area (7ft) with a radiator along some of the wall (it won’t be on) but it means the cage/pen can’t go right up against the wall all the way . I have cats so it would need to be both ferret and cat proof.

options I have thought of:

Make a wooden pen maybe with some perspex walls like people have for indoor rabbits.
cons
it doesn’t have a roof I would be worried about the ferrets escaping or cats getting in 
I would have to build it 
I don’t know how to add perspex and perspex would probably get expensive 
pros 
I can make it the 3ft width 
easy to access 

Wire and wood pen with roof 
cons 
If its 3ft wide I can’t access the back, would be a shame to make it only 2ft wide when it could be bigger.
Even if it was 2ft wide it still would be hard to access since it would be on the floor.
Probably would have to build it
pros
Both ferret and cat proof 
I can hang hammocks in it on the cage wire 

I could do some sort of pen and a ferret nation but I don’t really see a point to doing that, it still is a option 

[Corvidophile]

I built my own cage by using a glass and melamine jewelry display case for retail use, just made doors for what would be the back if you were using it for display out of hinges, wood frame, and hardware cloth stapled on. I’m very happy with how easy it is to get inside to clean. You can get them at stores’ going out of business sales. I would not recommend going topless if you have cats, unless the ferrets and cats are best friends already. Even then I think it would be best if the ferrets had a place to escape the cats (and vice versa). Most people, instead of going so wide they can’t reach over to the back, limit the depth and instead opt to go tall with extra levels they can reach, so a single level environment on the floor is a little limiting for that. You might want to build a cabinet type structure instead.

I don’t know about training out the biting unfortunately as I’ve only had play-nippers. The classic method is to use leather gloves at first when doing necessary handling from place-to-place and not let go when they bite, just put them down gently and then take off the gloves and start working with them bare handed once settled down and they can come up to you at ease.

[vivi]

My Luna was a biter . We used leather gloves and offer her salmon oil to lick . So she understood that our hands come with something delicious.
Now..after 6 years we kiss each other all the time LOL.