The safest way must be with a Cherry Picker, but you probably didnt want to hear that or ?.
There is no way a Gutter Vac system would work effeciently at that height, the weight would be too much and you would have real problems getting it between the Gutters and Tiles.
A ladder would work, but would be REAL work.
If you cant use a cherry picker and/or its too expensive, then leave it well alone.