check out his track record and picks ... he .continually has lagged just buying an s&p 500 fund .. he is an entertainer , no one should be following his advice and i think anyone buying or following his recommendations is wasting their time and money . his record speaks for itself . no further discussion needed , just google his record .
as far as what most cfp's recommend .. few recommend risk parity portfolio's . most are just old school indexing .. there are excellent risk adjusted portfolio's that do very well but the mount of gold varies in relationship to the percentage of equities ..
for 20 years now the harry brown permanent portfolio has beaten a 60/40 mix with 25 equities ,25% gold , 25% short term treasuries , 25% long term treasuries .
over the last 10 and 20 years the golden butterfly has beaten a 60/40 with 40% equities ,20% gold , 20% long term treasuries ,20% short term treasuries
https://www.marketwatch.com/story/jim-cramer-doesnt-beat-the-market-2016-05-13
as far as optimum gold there has been quite a bit of research on it ...