So I took the picture of your rear blade and crudely marked it up with Microsoft Paint.
I would take a 1/2" or 3/8" plate the same dimensions as your back end of your blade frame and drill and tap holes for 7/16" bolts (yellow in the pic)
To that I would weld a vertical piece of heavy wall square tube (2" or 2 1/2") (Blue in the pic)
I would "ears" on the top and back pf that to make the equivalent of a clevis or pivot point (gray round holes)
Another piece of square tubing back to the tail wheel (blue violet in the pic)
A 3pt top link on the top for adjustment (gold in the pic)
I admit that my mark up is crude, but if you start with attachment point to your blade and kind of fit it up and fab it up from there it should be fairly straightforward. They get $300, $400 plus to buy these as accessories if they are available at all. You might also want to make the horizontal and vertical square tubes welded on to your attachment plate to be the equivalent of
receiver hitches. That way the tail wheel would be quick attach and you could put a trailer ball on it when not using the wheel.