Push pull line stage

[battradio]

I have a pair of UTC A-18's and A-26's , and want to build a push pull line stage . Which of the triodes would be the most linear , 6dj8 , 12AX7 , 6SL7,6SN7
or 7586 with a with a 30k ct output transformer .
http://www.bunkerofdoom.com/xfm/UTC_1955_WEB/028.jpg

Mark