1) you can make your site to be joined by only men or women by editing the sex field in profile fields settings. Delete the option which you don't want to use. If required, also make similar changes to 'looking for' field.
2) For changing the age limit, go profile field settings and edit field date of birth. Make the required changes to the max and min values. This step also requires change in advanced settings which u've already made.
3) try doing it once again. Sometimes changes are not see more made due to some problems.
4) you pay only for ad-free license and not for any extra instructions. All dolphin docs can be found here: http://www.boonex.com/trac/dolphin/wiki/DolphinDocs
2) For changing the age limit, go profile field settings and edit field date of birth. Make the required changes to the max and min values. This step also requires change in advanced settings which u've already made.
3) try doing it once again. Sometimes changes are not see more