Welcome! Your video was actually one of the better gun videos that I've seen. You could have made it cleaner that the guns came in more than one barrel length. As is, it sounds as if the Sec-Six might have only been with a six-inch bbl., etc.
I've never seen that brand of ammo, and prefer that accuracy or expansion tests also be with better known brands that viewers will be familiar with and likely to seek.
Had you shown the explosive effect of a .357 bullet on a jug of water, that would have been convincing and dramatic. Many today do not realize the power of this load. It didn't shrink just because even more powerful cartridges came along. Your comment that it'll kill any animal in most of the USA is valid, but in fact, one famous Alaskan guide and his daughter use Security-Six .357's as emergency guns where big brown bears live! His published remarks in Handloader or Rifle (I forget which) were that placement is everything, and if well placed, a .357 will work. I have to respect his feeling, although I'd carry a .44 Magnum, the limit of my recoil tolerance and weight limitation.
You could have noted how the stainless construction and easy takedown make this series of guns good choices for use at sea or in coastal areas or in rain or cloud forest conditions.
The later, current, GP-100 series and the SP-101 share these advantages.
Your accuracy results show that you have at least fairly good shooting skills. Some post results on the Net that make it apparent that they have no business commenting on the accuracy of any firearm. However, testing at just 10 feet doesn't say much about the gun's capability.
You noted the substantial recoil with .357 ammo. You wanted Hogue grips. I suggest that you also consider the round butt Pachmayr Presentation Compac grips for this gun. It'll probably fit your hand better, conceal better, and hammer your hand less. That'd be my choice, and if I find one of these Speed-Sixes when I have the loose cash, I'll buy it and fit those stocks. If you are lucky enough to locate a Tyler T-Grip adaptor, that'd be a sound choice, too. You don't want to conceal carry, but many will, and in the right holster, it'll work. Depends on how you dress and how critical the concealment factor is. The smaller SP-101 will obviously fare better in some attire.
You may be interested to know that Winchester's 145 grain Silvertip .357 round will give 1200FPS in chrono tests that I've read, in three-inch barrels. The quarter inch diff. in your barrel can be disregarded. I think you'll get at least 1175 FPS from various loads in that barrel. Later editions of the Speed-Six did, in fact, have full three-inch barrels, but I think your gun looks a little better.
It'll also fire .38 Plus P ammo very effectively, and Speer's Short Barrel loads in .38 and .357 are ideal for your needs when noise or recoil aren't wanted. That info would have enhanced the video.
I think you have a very solid gun there, a little specialized in comparison to a Security-Six with a four-inch barrel, which would be a better general purpose .357. The adjustable sights would help. But if the load you're using shoots to the sights and ranges are not really long, that Speed-Six will do most of the same work.
Nice gun; nice video. I enjoyed it.
