I bought an alternative head for my standard 301 PanaVise called the PV Jr. I have posted a complete review here in Ramblin' Dan's Workshop. I thought it might be a bit more useful than the "standard" 303 vise type head. PanaVise actually makes a lot of optional parts or variations in holding devices.
I had a chance to use the variation shown here last night. I used it in just the position shown, tipped back a bit. I wanted to add a little more wax to the spruing of a wax carving I was readying for investing. I discovered I like the large flat pad area rather than the narrow clamping strip area of the "standard" 303 head.
This is not a heavy duty "saw and pound" set-up but it seems ideal for the, "I just have to hold it in this perfect position to add a drop of wax " detailing I always have to do. It is much more steady than I can hold it. Far better than piling bench debris up and hoping I can then prop my object at the right angle against the junk.
Yep, I think I will be happy with this new clamping device. It is also extremely easy to swap back to the 303 head when needed. One clamping knob.