You might look for the equivalent from ADI listed as AR-2209. Since ADI produces some of Hodgdon's powders it should be very close. It is listed in their chart as their equivalent.
While the copy I have doesn't list in particular the .260, it does list the 6.5x55 which could easily be used to work up comparable loads with. Also here is a link to their contact info, and you can download their latest data in PDF.
The newest data has quite a extensive listing of loads for the .260 Rem.
Hope this helps.