I remember in Factorissimo 1 that you could change some settings to actually setup solar arrays inside the factories, is it still possible to change some of the code to allow this to work, with changing some settings?

If you absolutely need solar panels to work inside factory buildings, you'll need to run the command

/c game.player.surface.daytime = 0.0

once while standing in each of your factory buildings that needs to have solar power.

Sweet, Thank You!

commences building an entire factory within one building

Inception Factory is being completed...routing everything and design are the biggest issues, Bob's mods add A LOT of extra stuff to route through the factory...

I'd love to see some screenshots.

Once its finished I'll post pics, still hashing out the design of the lower layers for manufacturing.