I'm keeping them indoors and would be super happy to share!
 
This cage has good enough size for a pair or trio (depending on your seramas' sizes) and that exact 3 pack is what I purchased. I use 
Quikrete All Purpose Sand as a bedding, mixed with a little bit of powder form 
Sweet PDZ and scooped with 
this right here. For waterers, I use 
pop bottle founts in combination with 16 ounce Pepsi bottles (strong plastic but slim, easy to get the spring around.) Use whatever feeder you would like, I suggest making a small PVC feeder or mounting a chick trough style feeder, something that gets it up off the ground. I don't provide grit because the natural sand does, but plan to put in free choice calcium in a little standard 
bird bucket feeder and if one wanted to provide grit it would be a good choice.
 
None of my caged birds are laying age yet, so I haven't tackled the issue of nesting boxes. I also take them outdoors, so I don't use UVB lighting. However, if your birds are not going to be in sunlight regularly, please consider a strip UVB bulb in each cage. Change it every 6 months to maintain effectiveness. Sunlight is very important for them! If you can build them a little A pen outside to put them in for a half hour at a time at least, it will benefit them greatly.
 
If you do not wish to stack the cages, you can give them even more room with 
the XL of this cage right here which a friend of mine uses for their two house serama. I need to stack my cages or else I'd use it instead! I haven't used it myself, but he loves it.