If you intend doing a significant amount of renders with the set, I'd put in the effort. Not sure how many poly's that set has out the box. IMO instances in larger architectural sets make a big difference on render times. That and lighting of course. If you do go that route, remember to use snapping where you can, to speed up placement of props, if the models permit. Also, set up keyboard shortcuts for both duplicate and instance creation. Good luck.