I was going to respond to this last night, but I don't really know that my answer is what you're looking for.
Square butts works better for me too on K and L frame guns. When I say better, I mean they balance better in my hand, and seem to help steady my aim. I have large hands so I favor closed backstrap grips so I get a proper trigger reach also.
On my round butt 686 PC gun, I use this grip made by Nill Grips, and sold in the US by Mactec.
http://www.mactecsales.com/SW038_p/sw038.htm
View media item 95For me, it balances out a heavy gun like the one pictured, and leads to much better shooting.
However on a gun I actually carry for defence, I don't want a thumb shelf, nor do I want a square butt grip sticking out and getting potentially banged into things. So on my 3 inch 686+, I use this grip.
http://www.mactecsales.com/SW039_p/sw039.htm
Again, it adds meat to the backstrap and gets me a better trigger pull. It also adds a bit of meat at the butt of the gun taking a round butt, and making it a round butt+, but not quite a square butt. I have never tried to conceal this gun, only carried it openly.
These grips are pricey, but worth it to me. They have quite a variety of grips and some with open backstraps if that's what you prefer.
As far as a technique goes, I have never heard of any particular one that makes shooting round butt guns any easier. Maybe pm MrBorland. He shoots a lot of competition, as do other members here, and see if they have a technique for you.
This is the set I want to put on my 460 magnum.
http://www.mactecsales.com/SW186PHG8_p/sw186phg8.htm
This monster is a little too pretty for the hideous piece of crap S&W put on it.
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