Too early to set up Machu Picchu. You can add the Regent trip to your booking to ensure you are booked. No extra deposit and you can cancel later
I am definitely going to wait until I return from my trip in November to make plans as there are some new properties I want to check out first. Definitely before anyone has to make plane reservations.
The trip I am doing in November is six nights and will probably do the same thing again. One night Lima, two nights in the Sacred Valley, two nights at Machu Picchu, one night Cusco. So of course my option will be more expensive. If you just want to see Machu Picchu quick then Regent could be a better choice.