How bad is it to memorize something with two different methods?

It depends on how many digits of pi you want to do in the end. If you’re looking at 500 total then you’d essentially rework 50% for reasons of “consistency”. If you’re looking at 5,000 - 10,000 digits it’s only 2.5 - 5%.

Not sure how you use your major system, but let’s say you place 5 digits per location, so 50 locations for the first 250 digits (roughly the 238 you mentioned)… how long does it take you to place those 250?

If it took you 5 minutes to do so, you’d get about 500 point in speed numbers in memory competitions. The world record is more than double that in 5 minutes. Say it takes you 10-15 minutes, then why not just do it if the consistency factor bothers you. If those numbers seem completely out of reach, it’s a whole different story…

You can also have a look here for some more ideas on how to structure the learning of pi: