That's a beauty! I was thinking about a K40 like that and getting it Mag-na-ported, or buying the ported Kahr barrel, but I got a P40 already ported... lighter for CCW, too.
Try a Sharpie pen or something like that. I was using one held in my mouth and positioning the slide and frame with my two hands. I just tried different parts of the Sharpie until I had the correct lineup, then I use a screwdriver handle to tap the slide lock pin out.
The first time I ordered something from Kahr, I got one of the $5 orange blocks for that... way over priced, but easy to use. Just use whatever's at hand that holds the slide open properly aligned.
Wynn
USAF Retired '88, NRA Life Member. Wife USAF Retired '96
Avatar: Wynn re-enlists his wife Desiree, circa 1988 Loring AFB, ME. 42nd BMW, Heavy (SAC) B-52G's
Frédéric Bastiat’s essay, The Law: http://mises.org/books/thelaw.pdf
Thomas Jefferson said
“A government big enough to give you everything you want, is strong enough to take everything you have.”
and
"Peace is that brief glorious moment in history when everybody stands around reloading".