Stamping, embossing, carving et al are subsets of tooling as a whole.
Your description of splits is far more charitable than mine - I won't use it for much, it represents a false economy in materials as far as I'm concerned.
Depends on the tan, really - this stuff was used for pouches for...
That said, 3.5 is fine - I've tooled some 2.5mm stuff that was OK, but I'd prefer not to repeat the experience (too thin and it gets mushy - calfskin is a real sod).
I've never had acceptable results tooling splits other than with a hot creasing tool, which has fuelled a prejudice against...
I know the site next door - access was a problem to that one (through someone else's field), which put me off somewhat. I doubt that Combat South have the same problem. I don't think I remember any boggy areas, but this was probably 5 years ago so I may be mistaken.
The "out of bounds" area was up for sale a couple of years ago. Nothing much in the way of interesting crops IIRC, the occasional redwood (!); not much in the way of stuff to forage, although there were some impressive funghi - although I didn't check to see what they were.
Please be aware that few engravers will be overjoyed to be asked to engrave already hardened blades - fundamentally, that puts the hardness of the graver at not much over the hardness of the blade... Engraving bolsters is possible, etching or burring (possibly drag engraving, not tried it) are...
It's a springer, not a PCP. Don't clamp it (you're constraining the recoil and you won't get an accurate zero if you do), just do as Red suggested and rest it on a bag of compost (or a sandbag, sand sock etc. etc.).
Hmm. I *was* going to say read Bladeforums - I haven't been there much the past few years, that's where I contacted him. Googling it, however... Yikes. I have a Roger Linger knife, I had no problems in the purchase, but that was at least 5 years ago, possibly more.
O1 vs D2 - both are...
I had a box with a number of BB in it. 2 mice got into it, shredded one pack... And died in the box. None of the other packs were touched. Never did work out a suitable LD50 for the things.
(and they're not bad with Primula :) )
The resulting shape is the one that needs to be balanced, not the sheet. Look at it this way - if you take a rectangle, the balance point will be at the centre. If you then cut a shape out of one end, that end will be lighter and shift the COG towards the other end.