“The eye, bhikkhus, is the ocean for a person; its tide consists of forms. One who endures that tide consisting of forms is said to have crossed the ocean of the eye with its waves, whirlpools, sharks, and demons. Crossed over, gone beyond, the brahmin stands on high ground. The ear, bhikkhus, is the ocean for a person…. The mind is the ocean for a person; its tide consists of mental phenomena. One who endures that tide consisting of mental phenomena is said to have crossed the ocean of the mind with its waves, whirlpools, sharks, and demons. Crossed over, gone beyond, the brahmin stands on high ground.” - SN 35.228
Regarding the linked essay, I don't I agree with the point about yoniso. In Tibetan the term is translated as tshul bzhin, which means "properly". The Tibetan translators worked closely with Indian panditas to come up with their translations, and often lived in India for long periods of time, so I don't think their understanding is trivial.
Also, the Bhikkhu argues that yoniso cannot mean "properly" because it occurs in a collocation with sadhukam (sādhukaṁ yoniso manasikaroti), which already means "properly". The idea is that a word wouldn't be used redundantly. But redundancy is extremely common in Pali literature (and Indian literature as a whole), so if anything I think that is a counterpoint to the Bhikkhu's argument.