Well you're creating an animation and an animation takes time to play, so you could increase/decrease the duration of either of the two animations. (they are both set to 5 seconds at the moment, so setting one to 10 or 2.5 seconds will make the other twice as slow.
Keep in mind the total duration of the timeline gets converted to the total scroll distance if you have have a timeline with scrub: 1, see the following tutorial.
If something is not clear, just try to modify the property to see what it does, reverence the docs if it then still isn't clear and if you then still have questions post back here. We're happy to help.
Happy tweening!