I am just curious how much time and effort I should put into some of this or if I should just "put my faith in Microsoft" and that DTA knows what's best.
The DTA does not always know best. I've found that it tends to go overboard.
When I use it (which isn't often) what I'll generally do is implement its suggestions 1 by 1 and test the performance improvement, then I implement the ones that have the most impact.
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)SQL In The Wild
: Discussions on DB performance with occasional diversions into recoverability
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