1. how can I increase the number of lines above the 'See more' link on the events tab?
There's no parameter for that, but you can extend it using CSS. Example as follows.
Code:
.cb_template .gjGroupEventDescription .cbMoreLess.cbMoreLessClosed .cbMoreLessContent {
max-height: 200px !important;
}
That would double the height (default is 100px). You can add this quickly and easily using the built in CSS overrides functionality below.
www.joomlapolis.com/blog/kyle/18711-template-css-overrides-made-easy
2. how do you suggest that I list an overview of all the events on an 'Events' article linking each one to the corresponding Groupjive group and -events tab or even -event?
There's no functionality for consolidating group events into a single display. There's plans to support this in the GJ module at some point, but it's not available at this time. Best I can suggest is maybe CB Activity since you can use CB Auto Actions to generate an activity entry when a GJ event is created, which will display on the activity stream.
3. is there a way to display a my events on a CB tab or is this configured elsewhere in the user profile?
No, please keep in mind GJ is not an event manager. It's a community group manager.