/vr/ - Retro Games

I can't into outdoors mapping, can anyone help me here? We see an outdoors area (ignoring the default floor texture). In there I've placed a few walls which are 128 heigh by raising the floor of those sectors. The ceiling of walls/outdoors/inside is currently still at 512. Now, if I lower the ceiling of the building and swap texture to something more appropriate for inside (ie not sky), I either get hall of mirrors effect (no texture on upper side linedef), or just an incredibly tall building. Should I just make all my buildings the same height and set the outdoors sky/ceiling height as that? Is there something else? This is why I prefer indoors darnit.