Pardon my "tone" as I worry every time a thread like this happens. I do not understand pushing the envelope so to speak. I say why? We know what's safe, we know what works. These things are affordable and readily available. To my mind, there is no good reason to chance it.
There are a numer of threads on this. Most recent is the one you reference. Tim has stated numerous times of early cast rec per SB1. Current SB1 and stronger SB2 receivers. Remember to watch firing pin sizes for SB1's if CF loadings are to be used.
It sounds to me like you want irreputable iron clad facts. What we have given is our opinions, you need more. No one here can do that ceptin' the factory and I seriously doubt they will tell you for lyabilitys. The stand will be the gun is safe as delivered. You modify your on your own. The Versa Pak comes with a 22RF and a 410. The huntsman is a blk powder, likely same as early cast or current SB1 frames. If you want a 12 or a 44 buy a SB1 or Better yet SB2 and don't worry.
The consensus here is SB1 is fine for a 40k cup caliber, all shotgun and blk powder barrels. SB2 for ALL calibers. YES the Maxi is safe on a SB1 as long as you safely load for it at factory levels. My my first MAX came on a Topper 158 frame.
If these opinions are not to anyone's satisfaction contact the manufacturer. Brian is on here all the time PM him for the info. BUT know that in today's world it may well be filtered thru a lawyer so take it as given free info.
As I have stated in all such threads I have commented. The versa pal frame is a bit of a mystery. I have no desire to be a static. With all the easy availability to frames of known rely ability and safety WHY chance it. Before someone comments about not having $$ to do that. I say how much value do you put on your eyes, face hands or even life! I know mine is irreplace able to my family and myself.
I am not saying it will blow up, what I am saying is we do not know so why chance it! Everyone assumes its like a SB1 and for the most part, I agree. But I am not willing to prove that.
Merry Christmas,
CW