flex liner and cleaning xxv?

I am putting in an xxv stove into a chimney using the top vent option. not sure which way to go to run the pipe, as far as solid piping vs the flex liner. the chimney has an 8" clay liner i believe. It also has an outside cleanout about the oposite of the inside opening. If using a flex, how do you do a cleanout of the chimney (liner from the top). If brushing ash down, how do you vaccum up the ash then? piping recomendations would be very helpful. thanks....

jim