Cage upgrading advice needed

[Maisiepaisie]

This is my cage as it is now:

Its a 2 tier 2x7 however I'm don't need the lower level anymore as I only have 5 pigs now and they live together. I've been pondering for a couple of weeks now whether to adopt a couple more pigs to go in the empty cage but I decided it would be better to give all my attention to the pigs I have and make their environment bigger and better. I have a new piece of coroplast as that one is looking rather 'pig eared'. I plan to remove all the supporting grids leaving just a 2x7 plus the floor. With these grids then I will build a 1x3 extension on the front at the same level. This will be the hay zone, freeing up the main part of the cage from hay so the fleece can stay looking nice and tidy (hopefully). I also want to build a 1x7 upper level across the back but I might have to abandon that until grids become available in the UK again as I may need the grids for a stand.

My question is should I make a stand out of grids or place it on a table? Its all going to be extremely heavy and as it is now I wouldn't risk adding anymore grids. The supporting grids would need to be arranged in a stronger way than they are now to support the weight of the cage plus the added extension and eventually an upper level.

 

[Maisiepaisie]

I just spotted this https://www.guineapigcages.com/photos/showphoto.php?photo=1218 Maybe I'll do it like this and bring those support grids under the 1x3 extension as well. Ideally I'd like a bit more free space underneath but like I said its going to be really heavy so will need plenty of support. Do you think this design would be strong enough to support a 1x7 second level?