That’s a great start, @fecmgrcavlb . Here we have the training page of pi. You can react to random n-th digit to pi, pretty handy. http://i.artofmemory.com/games/guess-pi
I am pleased to answer one of your question, you said it’s difficult to fetch certain n-th memory item in your mp, right?
This requires a specific skill, called “paging”, which means you have to set-up page markers, say every 10 loci (4 digits stored per locus), you mark it with a specific code, say a big red pin 
in somewhere of your palace.
When doing the test, eg 873-th digit of pi, a quick math is carried out = 873 / 40 = 21 ~ +33 or 22 ~ -7.
You then 
running through to markers 22 back steps 7, get the answer “3”.
This method is common used in electronic machines, because of energy-saving between memory switch.
One 
thing you have to consider thoughtfully, is the paging size if it’s too big fetching could be difficult; paging a very small amount of data, is not better than walking through all the loci once.
Another rule of thumb, for a small data set below a hundred of items, link method is the best method in terms of 3R, records, recall and revise. All you have to is to link everything with a your peg list accordingly.
I hope those info can be useful to you. 