Dim weight products shipping calculation

FBM, 90% of our products are not affected by dimension weight or surcharges.
The remaining 10% or so boils down to:

Long skinny packages, think 36x6x6 that vary in weight from 3lb to 30lbs.

“Panel” style packages, think 24x24x4, 36x36x6 that are typically less than 5lbs.

These products are typically slower moving, but larger margin than the 90% of products that aren’t affected by dim weight.

The problem is, we have never once been able to get the shipping template calculated correctly to charge enough shipping to cover the ship cost on these items. Due to the NPM% on these items we are happy to eat the difference in shipping on these items as we work towards a solution as Amazon does not auto-calculate shipping charges based upon Dim/weight, as most other platforms do.

A colleague suggested using the dimensional weight in the listing for these items so as to calculate a more accurate shipping charge for our buyers, and purchasing labels with actual weight + dimensions. This would mean a 30x30x6 4lb package would go from 4lb to 33lb with USPS or 39 with Fedex/UPS.

What is the general consensus on doing such, and are there any better alternatives for these edge case, heavily dim-restricted products?