Wish there was a 'destroy non-economic non-ore stone' option... Or destroy stone by type. So legendary miners could be told *not* to leave rock behind...
And/or sub-designation of specific areas to be dug out to particular high/low skilled dwarfs, or with the same skill-level cut-offs. (New miner? Train him on the hewing out the huge gabbro cavern while the legendary ones get assigned the gemstones.)
Regarding accurate SISO, it would of course rebalance the game drastically, but treating a tile's-worth of stone as a volume from which seven layers of raw stone can be removed (eight if it's a floor-removal one), each of which is capable of forming something like a stone table (imagine cut and divide both two sides down to get legs and a nice rectangular surface, if originally square, and of course block-cutting it beforehand would make that process tidier, but it would end up essentially occupying a tile's-worth of space) or multiple smaller items after processing would allow degrees of "useful product" and (
if deemed something Toady wanted to do) spoil. (Any difference from the nominal total being expelled as dust. Normally below the cave-in level, for which I'm sure dwarfs have evolved anti-silicosis mechanisms so won't be adversely effected, but intensive mining far from ventilation might cause problems. Maybe that's why you need expert miners, to make the job as un-messy as possible.)
But without some sort of rejigged hauling problem, you're still left with the fact the stone 'ought to' occupy a larger amount of space. In a stricter system, mining should not leave slabs/spoil on the spot you've mined out, but shuffled to the rear (or up/down a shaft, assuming sevenths(/eighths) of a tile could reasonable be assumed to be portable up or down such stairs). And after more than a couple of slabs have been propped up at the sides of the access tunnel (frexample) you'd need to send the next block, or quantity of waste material[1] back to another (adjacent or further back) tile for storage, until your miners, mining support workers or pit ponies (or conveyor-style mechanisms, should they be available) clear out more space adjacent to the space to allow more immediate digging.
But that's of course a great leap of change of functionality and distribution. I'd not advocate it as a change. Which is not to say it might not be workable, with a comprehensive-enough revamp. (Playability and reality checks are largely independant entities, and I'm sure everyone has their own preferences as to what order they would place the point of balance.)
[1] I think I've previously classified it to four levels, which I shall recast for the above pondering as follows:
- Large rock chunks (in this case slabs), from which large items can be made (or essentially slab-sized blocks from which large items can be produced)
- Useful rocks, from which your classic rock mug, or several earrings, can be hewn. (Could be worked into small blocks beforehand?)
- Spoil, much like gravel. Useful as 'filler' for block-based walls, perhaps, but certainly consider using as part of roadmaking agragate. (As an afterthought, extraction of gems might require the rock to be pulverised.)
- Dust. Inconsiquential apart from choking hazard.
(Sandstones might actually give 'sand', at level 3.5, or you just assume that that's something that can be processed from the sandstone spoil. In the way that limestone spoil is processable to quicklime by the right manufactury.)