Black Dog pd1

The next I decided to lean for my solo performance was black dog by Led Zeppelin. The first target I set myself was learning the main guitar riff that is played many times throughout the song.
The song uses mainly uses notes from the A minor pentatonic scale including the notes a, c, d, e and g however Jimmy Page is adding the note G# which gives the rif a sense of chromatic feel as part of the riff goes from the note G to G# to A and these three notes are played on the D string on the 5th, 6th and 7th frets of the guitar. 
Here is a tab of the riff:

E|-----------------------------------------------------------------------------------|

B|-------------------------------5---------------------------------------------------|
G|-----------------5^~--------7-----5--7hp5--------5^~-------------------------------|
D|-----5--6--7-----------7-------------------7--7--------7----5--7--7-------------2--|
A|--7-----------7------------------------------------------------------5--7\3--5--0--|
E|-----------------------------------------------------------------------------------|

I will be focusing on getting the timing of the riff right as the riff is played in 5/4 over a 4/4 beat which makes the timing of the riff very odd.  I will also need to make sure I get the hammer on/pull of section of the riff right. (5--7hp5  on the G string part,) 
I will practise this riff for around 30 minutes a day as this will give me enough time to learn the riff if i keep playing it over and over again starting of slow. Once i can olay the riff at full speed I will practise it over and over again with the original recording of the song.
This is relevant to the song as this is the main guitar part in the song and if it isn't played right it will be very noticeable and the song will not sound right.
This should probably take me around 3 days to learn if I practise it 30 minutes a day as the riffis challenging but 3 days should be enough if I break the riff down into different sections. on the first day I will practise up to the hammer on part:

E|-----------------------------------------

B|-------------------------------5-------
G|-----------------5^~--------7-----5--7hp5
D|-----5--6--7-----------7----------------
A|--7-----------7-------------------------
E|----------------------------------------

On the second day I will practise the second half of the riff (red:)

E|-----------------------------------------------------------------------------------|
B|-------------------------------5---------------------------------------------------|
G|-----------------5^~--------7-----5--7hp5--------5^~-------------------------------|
D|-----5--6--7-----------7-------------------7--7--------7----5--7--7-------------2--|
A|--7-----------7------------------------------------------------------5--7\3--5--0--|
E|-----------------------------------------------------------------------------------|


On the 3rd day I will practise playing the song up to full speed and along with theoriginal recording.