Only one topic(*) generates more forceful arguments between sailors than anchoring.  All real cruising sailors have strong opinions about what works. So I comment with humility...

I am not a fan of tandem anchors.  To my thinking it is an idea far better in theory than in practice.  But...if I needed to for some reason, I would follow the advice in this article of Peter Smith's (designer of the Rocna anchor): https://www.petersmith.net.nz/boat-anchors/tandem-anchoring.php

If you are lifting your anchor with an electric windlass, there seems little reason to have less than the biggest anchor you would ever use as your primary anchor on the bow. While this is not a place I like to carry extra weight, the difference between a "normal" and a "serious cruising" anchor is certainly not more than 40 or 50 pounds.

The single biggest problem with the tandem system is that I am most worried about my anchor's security during dramatic wind shifts.  This is exactly the time that the extra hardware on the bottom can be more problem-causing than problem-solving.

(*) The one more contentious topic:  "Mono or cat?"

Bill Kinney

SM160, Harmonie