In this case, when I am sure what i want to achieve - it takes arround 6-7 hour with modelling/materializing and rendering (render takes something about 1 hour). But as you can see that they arent so complex:) I hope that this practice will make my own production much quicker and better:)
Anyway in Blender I do not have RT and even material preview so for the lighting previews I am using Cycles which gives accurate postions of hdri rotation in Corona. Using proxies for models like people or furniture speeds up the export time, so I am quitte hapy with currently speed of exporter. Of course vegatation is added as the last, because it increase export time a little:)