You should go for it, yourself.
I used the Sears die grinder assortment, ($6.00) after the 1/4 then 3/8 bit was run through.
I chose a die grinder bit, instead of the select-a-hole drill bit, because it was too expensive and there was no way to be sure the pilot hole drilled, was dead center. Even if I used the expensive 1/2 inch chucked select-a-hole bit, there is a rather large chance you would have to tailer the hole by grinding, anyways. It's very tough to center the first hole "perfect".
Skip the select a hole bit and just use the round ended die grinders, with a bit of the strut oil, as lubricant. The mild steel can be Dremel'd easily, if you save the smaller Dremel cutters, (preferably the newer style, with the bow-tie center hubs in them), as you grind them down cutting the strut tube ends and shortening the bolts.
Then the smaller wheels, you have saved, which are pre-sized, will fit into the strut tube holes you have wallowed out with the die grinder, so you can smooth the internals of the strut tube, exactly to one inch for the shortened inserts. The lil' Dremel works great for fine tuning and cleaning any lumps or slag which might stop the strut from seating correctly, as well.
The red insert Greg V sold me for $60.00 had a larger than stated strut nub, welded on the bottom of each insert. It wasn't 9/16, but rather a full 1 inch, so the holes came close to the welds around the donor tubes.
I made sure the bolts didn't bottom out on the cartridges, and every one had to be shortened more than I originally had them cut down to. Also noticed a bit of welding lump on the Koni's which was easily removed with the smaller Dremel, along with the paint, so the epoxy sticks correctly.
I'd say there were six threads cut from each bolt, not four like the write up stated, but that's because the struts have been improved and I didn't want to take a chance on the bolts cutting into the cartridge base, which they will certainly do, if they are too long and over-tightened.
Thanks Steve, wherever you are!