The article you linked promotes terrible misinformation on the meaning and effect of swappiness.
Don't tweak what you don't understand.
The parameter value set to 60 means that your kernel will swap when RAM reaches 40 capacity.
That part of the article is total garbage. The rest of the article is based on that fundamental misunderstanding, so the whole article will just misinform.
A much more insightful simplification of the meaning of swappiness, would be to say that it represents the relative cost of spilling and reloading anonymous memory vs. non anonymous memory, where a swappiness of 100 implies equal cost and a swappiness of 0 implies non anonymous memory spills and reloads at zero cost.
Using a single traditional hard drive, anonymous memory spills and reloads (through swap space) for on average twice the cost of non anonymous memory reloading from its file backing. A non symmetric performance media (flash) would tend to increase that two to one difference (so optimum swappiness would be lower than the default, but not as low as zero). Multiple and/or mixed media may have a complex impact, generally not worth micro managing. If most rereads are from flash (rather than traditional hard drive) lower swappiness for better performance.