I make a great deal of use of the Skeeter load. With Elmer's Lyman #429421 bullet cast from wheelweights I get great accuracy and adequate punch for anything I'm likely to need a handgun for. And the load is perfectly safe in just about any .44 Special made, thought I'd limit it's use in small, turn of the century guns.
Keith's heavy load was 17.5 grains of 2400 with the same bullet. This grossly exceeds anything listed in the manuals and is probably unsafe in many guns. But the Speer lab supposedly tested this load and found that it generated 27,000 PSI, which is quite a bit less than the typical .44 Magnum load, so there's good reason to believe the .44 Special Keith load would be perfectly safe in a Magnum. And it follows, of course, that the OP's load of 15 grains would be fine as well.
As for the danger of dropping such a load into a lightweight .44 Special and turning it into confetti, that's a reasonable concern, IMO. But those of us who have been turbocharging the .45 Colt know that there are ways of preventing such problems, like using only certain brass for the hot loads (my "safe" loads are always in nickeled cases, and my "hot" loads are exclusively in Federal or Starline brass) or only certain bullets for the hot loads (my hot Colts use LBT style bullets exclusively; everything else gets SWCs or LRN).
Now, I have to admit that I don't quite see the point in the Keith load anymore, unless one is trying to get Magnum results from an N frame Special. The .44 Magnum works so well at higher velocities and pressures that it's hard for me to understand why anyone would bother with the Keith load, nostaligia perhaps excepted.