The mounting plate to put the servo on the tail does have oval holes, not a problem, just bolt it on. Collective servo mount is backwards? Are you using the push/pull? If so.... Install the push/pull assembly so the linkage is straight down from the tray to the assembly. Adjust the linkage so your head is centered. Install the servo and adjust the lingage to the push/pull assembly with the servo centered, if it travels the wrong direction then reverse the servo. Hope this helps and is what you were asking.