"Stoving" is a somewhat vague term that always refers to heating the tobacco. The divergence is that "stoving" sometimes refers to baking or toasting (under a confusing range of temperatures and durations), but may sometimes refer to applying moist heat (e.g. steaming). Higher temps usually result in darker tobacco: darker red, brown or even black. Steaming darkens tobacco to brown and eventually to black. Nearly all of the "stoving" techniques used by commercial pipe tobacco manufacturers are closely held proprietary secrets.
Some commercial stoving methods continually toss the shredded leaf within a rotating drum that is heated. (I consider this toasting. This is how cigarette manufacturers "toast" their burley.) Others use a "steam jacket" for the heat--a description that may mean steam-heated press plates, or may mean a mechanism for actually delivering the steam to the leaf.
The common thread is that both dry heat as well as moist heat will alter the color and flavor of the tobacco in ways that invite experimentation.
Some purchasers of tinned tobacco "stove" it in a hot car, or even in a Crockpot, with wildly varying results, depending on the tobacco blend, the temperature reached and the duration. The outcome can be wonderful or horrible.
One approach to stoving leaf at home is to pack it into a canning jar (e.g. Mason jar) and seal the lid. This can then be placed into a pot (or Crockpot) of water that is heated to a specific temperature (like sous vide cooking) for a carefully measured duration. Or you can cook the jar at boiling (or higher, in a pressure cooker), until you get the color desired. A variation of this method is the spectrum of initial leaf moisture, from nearly dry to soggy.
You can also just pile leaf into a colander that is placed over a pot of boiling water. (I regard this as essentially a Cavendish method.) Turning it completely black takes about 8 hours of steaming. Done similarly in a pressure cooker (i.e. leaf exposed to the contained steam) takes about 5 hours to blacken tobacco.
Some folks place shredded tobacco onto a cookie sheet, and toast it in the oven, periodically taking it out and misting it with water (or casing).
I have placed beautiful lemon Virginia flue-cured tobacco into a kiln at ~125ºF and RH ~75% for a month. The leaf came out redder, more flavorful and less acidic than the original lemon Virginia. I don't consider this better, per se, but rather different--yet another blending component.
The usual flue-curing process destroys (at ~149ºF) the most active cellular oxidase enzyme (responsible for "aging"), but not the less active cellular peroxidase (~191ºF). So flue-cured tobacco (typical max temp of 165ºF), if left alone, does "age", though fairly slowly, when compared to leaf that has never been taken to a temp as high as 149ºF.
Although many popular commentators (e.g. GL Pease and Russ Oulette) attribute aging to microbial processes, I believe most changes of aging are the result of cellular oxidizing enzymes. BUT, if you press the tobacco, rupturing the cell membranes, as is done in press blocks, press cakes and Perique manufacture, then the cell contents of different tobacco varieties in the blend do meld, and if kept moist enough, will encourage microbial activity that significantly affects taste and aroma.
Rule of Thumb for Stoving Tobacco
There are no rules. Enjoy experimenting.
Bob