I'm not super convinced by the interest of slabs of accreditation in fact. There is a lot produced, so it forces you to have alchemy workshops nearby the training dummies, which is not super logical (I would prefer to leave them in barracks e.g).
I understand that any reaction need to produce something though... So here is my proposed rework... And it would add money to the game, see
http://www.bay12forums.com/smf/index.php?topic=107791.0Basically, you mint money to get coins. Coins are used for a lot of stuff: training dummies, do alchemical reactions, anything fancy should cost money, as you pay the dwarf to do his work. You would also do alchemical research by spending a lot of gold money.... and if you need gold, you can transmute stone to gold, so you can't be stuck here...
Slabs: alchemical workshop can produce one slab for xxx gold coins. A training dummy needs one slab to operate (plus some coins for the drill master) and produces... one slab. Basically you don't spam slabs as they are continuously produced.
A refinement of the system that I would prefer is that a training dummy costs 5 slabs and produce 4. So from time to time you have to buy new accreditations at the workshops, for a few coins, coins that you would mint with the gold bar you transmute!
Last point, I think that the transmutation of 10 stones to one bar of gold is too generous. I understand that the hidden cost here is that you have to haul 10 stones. Still, even taking that into account I think a cost of 15 stones would be more fit. Obviously this is my point of view on a cost balance, but I have played quite a lot this mod lately and you can really generate a lot of gold bars that are worth quite a lot too once re-manufactured... So I advocate the 15 stones cost.
Narhiril, I would really like you to see interest in my proposal of minting gold bars into gold coins and using this new dwarves money into a lot of new (or not new) reactions, as part of the cost. This would be a new dimension in DF... You could create shopkeepers, black market etc. that would sell stuff. This would also unstuck players from some dire situations. Say you really need one bar of soap or plaster. For a high price (because you want that to be a pricey solution) a shopkeeper would sell you one. Etc.