Is an open day an option? Clearing the house for one day may be one way of doing viewings en masse and it can work! Getting the house ready for one day can be hard work - but you have to be confident you can pull it off within the given timescales.
What about asking the agent to organise viewings following each other, give everyone half an hour or twenty minutes and then you can do the tour several times in one day.
This means you've got oen lot of tidying up to do and you get it over with in one go. You have the downside that people might well want to come back for a second viewing which means you've got to do it all again!
Your tour spiel will improve the more you do it so it's worth rehearsing it too.