If you are talking about memorizing the precise order of a 26 card slug and not just the count of the slug (i.e. 2 of spades, 7 of hearts, 8 of spades, ect ect) i'm not convinced overall that it will be a whole lot of use to you. That slug would have to be mixed precisly with the other slug you've memorized and each time they riffle the two grabs together after the first time is going to break the sequence.
However if you can find a situation where this happens and the dealer is very accurate with his/her riffs and riffs the cards only twice, after seeing the first card you will know what the 5th card and the 9th card ect ect. After seeing the 2nd card you should have a good idea what the 6th card and the 10th card will be. This is where it all gets very complicated and you start to get bogged down with all the different parts of the two sequences that you'll have to pull out.
Overall the right situation is going to happen so infrequently and the technique is going to require so much mental endurance, i'm not convinced that using this technique solo is going to be worth it. Now a team, that's a different story.....
RJT.