This first riff is a Meshuggah-esque riff in the sense that we're playing a measure of 13/16 under a basic drum groove of 4/4. After three whole bars, the meter still has not reset, so you'll have to pay close attention to the transition from bar 3 back to bar 1.
An Easier Approach:
Take a look at bar one. The way I approach these riffs is to try to block out the snare drum beat with as much effort as possible. By doing this, you're making an attempt to block out the 2 and 4 pulse. This is important because it'll enable you to play the meter with greater ease. Analyze the sequence in bar 1 up until the end of the 2nd "Ebm" chord; this is the entire sequence that will be played three times. If you think of it as that short sequence being played three times, verses 3 full bars of complex meters that continually change starting points, you'll have a much easier time.