This conversion will be similar but not so big as was the vc10 to royal flights, just a vip fit, it is a "simple" role change one lot of kit out another one in.
However I doubt if it will involve the engineering prep for a royal flight (long distance tour) where major components over half life were changed ie engines etc and a fully fitted reserve aircraft followed it once it was 1/2way to next stop, and a herc ahead with all the baggage.
Seems a much cheaper option than chartering to me, re crews surely they are not supplied by airtankers company.