Upper-Class/Posh Formal Received Pronunciation (Conspicuous General British English) well-educated
How do you do, eveyone!

There are more formal pronunciations of the Received Pronunciation chiefly the Upper-Class version. I have known the following are well-educated/upper-class/posh pronunciation.

examples:
-
data: DAHR-tuh instead of DAY-tuh (I wonder how come it is UK formal? see https://en.wiktionary.org/wiki/data)
apparatus: ae-puh-RAHR-tihs
mass (as in the Catholic mass): MAHRS
scone: rhymes with "loan" rather than gone (also in General USA)
renaissance: ri-NAY-SÃS rather than ri-NAY-since since it is a French loanword. Where ÃH is the nasal vowel. (see https://en.oxforddictionaries.com/definition/renaissance)
waistcoat: rhymes with west kit
golf: the l is silent
**off: it pronounces as ORF
**often: rhymes with orphan
**lost: likewise with saying off and often which the "o" is pronounced as in 'thought'
(**see Her Majesty the Queen's 'The Christmas Broadcast 1957')

also there is hw pronunciation for what, when, and which!

see comment to read part 2 of my question.

Question

Upper-Class/Posh Formal Received Pronunciation (Conspicuous General British English) well-educated
How do you do, eveyone!

There are more formal pronunciations of the Received Pronunciation chiefly the Upper-Class version.  I have known the following are well-educated/upper-class/posh pronunciation.

examples:
-
data: DAHR-tuh instead of DAY-tuh (I wonder how come it is UK formal? see https://en.wiktionary.org/wiki/data)
apparatus: ae-puh-RAHR-tihs 
mass (as in the Catholic mass): MAHRS 
scone: rhymes with "loan" rather than gone (also in General USA)
renaissance: ri-NAY-SÃS rather than ri-NAY-since since it is a French loanword.  Where ÃH is the nasal vowel. (see https://en.oxforddictionaries.com/definition/renaissance)
waistcoat: rhymes with west kit
golf: the l is silent
**off: it pronounces as ORF
**often: rhymes with orphan 
**lost: likewise with saying off and often which the "o" is pronounced as in 'thought'
(**see Her Majesty the Queen's 'The Christmas Broadcast 1957')

also there is hw pronunciation for what, when, and which!

see comment to read part 2 of my question.

Answer

Isn't RP becoming a thing of the past? I'd be interested to hear what the Brits say about this. Speaking RP might end up making people laugh, rather than impressed...

Answer

here is part 2 of my question.

Before replying...

Here are the words that have plenty of pronunciation.  I am looking for the well educated and upper-class formal not informal pronunciation.  I would like to learn more British and somewhat International pronunciation and willing to avoid USA-exclusive pronunciation such as for adult: UH-dult instead of AH-dult (AH from cat).

I know the well-educated/formal/upper-class RP speakers prefer to pronounce any foreign language with a foreign pronunciation like French and Latin (somewhat almost).  I would like to combine have my URP English and Japanese loanwords with proper Japanese pronunciation rather than Anglicized since I am learning Japanese.  
e.g for kawaii: KAHR-wahr-ee instead of KUH-wai. 
 I would like to pronounce more British and not much American (saying scone is fine) Can anyone give me more formal and well-educated pronunciation?  I sincerely apologize for the enourmous and complex comments and I sincerely appreciate for your biggest assistance.

P.S. I am willing to change my accent from a mixture of Filipino and American to General American to an Upper-Class, Formal Received Pronunciation (around Southern England mainly between Oxford, Cambridge and London) as a Filipino from Bacolod City who lives in Myrtle Beach, South Carolina, USA.  Wish me the best of luck! =)

Spelling: British English - Oxford Spelling

references:
Upper British RP
https://www.youtube.com/watch?v=Rwnpg33bRO8&t=559s

Wikipedia: Received Pronunciation - Conservative RP
https://en.wikipedia.org/wiki/Received_Pronunciation#Conservative_RP

The Guardian: How to talk posh: a rarely marvlous glossary
https://www.theguardian.com/lifeandstyle/2014/sep/22/how-talk-posh-glossary-non-u

How to sound posh - Part one
https://www.youtube.com/watch?v=Nj0Rh__1kDw&t=112s

How to sound posh - Part two
https://www.youtube.com/watch?v=-iW7HxCi5d4&t=186s

iswearenglish - YouTube