I know I wouldn't trust one single translator to accurately translate the suttas, so if I placed as heavy emphasis on the Visuddhimagga as you do, I certainly wouldn't be relying exclusively upon a single English translation, without knowing the Pali underlying it. This is especially so given the regard in which venerable Nanamoli is reported to have viewed the work - viewtopic.php?f=14&t=4648
. Furthermore, post Visuddhimagga translation, Nanamoli Bhikkhu's understanding of the Dhamma changed somewhat and when translating the Majjhima Nikaya, he translated certain terms in a different way to what he had done when translating the Visuddhimagga. Bhikkhu Bodhi didn't approve however, and took it upon himself to re-translate parts of Nanamoli Bhikkhu's original translation manuscript, back in line with the earlier precedents... hence the dual translatorship attributed to the Wisdom Books translation of the Majjhima Nikaya.
I guess how much confidence you place in Nanamoli Bhikkhu's translation is up to you to discern.
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"The uprooting of identity is seen by the noble ones as pleasurable; but this contradicts what the whole world sees." (Snp 3.12)
"To argue with a person who has renounced the use of reason is like administering medicine to the dead" - Thomas Paine