I did something very similar to what Vern did. This puts the servo in the bay forward of the main spar. Having the servo there makes it much easier to maintain and repair. Over the years, 12, I have had to replace my roll servo three times. The heavier roll forces of the EVO wing may have had an influence on that issue. The "tab" does not have to be on the bottom of the tube, mine is on the top. The point is to measure the distance from the tube to the hole in the supplied bracket and then make sure that your tab is the same distance away, be it on the top or the bottom of the tube. Check that the range of movement is such that you never get into a position where you can go "over centre" . This check should be done however you mount any of your servos.
Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average
speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger
St.Thomas, Ontario Canada, CYQS