I used most of those as well as weighted dips for my bench routine that I got from a world class bencher (4th in the world) and any form of dumbell work was specifically NOT used because he didn't believe that there's enough bench strength carryover with dumbells.
Weighted dips were part of my assistance work with floor presses and close grip bench.
As for the original question, my weighted dip is approx. equal to my decline bench. I weigh 180 and use a 105db for 5X5 weighted dips and use 275 for 4X6 with declines.
My regular bench is slightly higher than my decline and I think that's only because I only started declining about 2-3 months ago.