Thanks for the photo link
The arrangement I have substituted for the cane seat looks like the contoured seat in your photo (homemade) but sitting on 6 inches of foam underneath instead of on the wood frame. I notice the angle blocks in the photo are about the same depth and angle on the vagabond. I would have to add a two inch spacer and longer bolts to get the seat as low as what I am currently experimenting with. In that position I can’t get my feet under the seat to kneel so have to sit feet forward anyway. However, I can adjust trim easily by moving the position of the seat I am now using on the bottom of the canoe, and it lowers my center of gravity.
My derriere on the stock seat actually needs to be about an inch higher than it is for my bent knees to be comfortable, but that brings the seat up under the gunnel and increases the height of my center of gravity.
I might be persuaded to consider the seat you have. Email me the particulars.