Your question is in fact much wider than that, it brings to light the connection between herbalism and homeopathy, and there is a full book on the back-burner about that....
In short, if you look at the traditional indications of herbs that are common to both practices, you will see that the herbal indications of a plant are all included in their homeopathic MM, then expanded as the process of potentisation widens and deepens the abilities and indications of the remedy.
Another way to look at it is that herbal remedies prescribed according to old traditions are in fact prescribed homeopathically unbeknownst to the prescriber. Once upon a time on one of the herbal discussion lists I belong to, someone asked "what would be the smallest dose of tincture to be still effective?" A very experienced herbalist, much respected and followed in the community answered "one drop if the remedy is properly chosen".
We can also look at it this way: it depends what you want to achieve: do you want a pharmacological, biochemical action, in which case you need a tincture and a material dose or do you want a physiological or energetic action in which case you need a more diluted and "subtle" dose......with huge grey zones between those.
Some years ago at a herbal conference, we had an argument between drop dose prescribers and let's say more significant material doses prescribers. One practitioner, who is a phytopharmacologist and knows his stuff extremely well, described a situation where he had to give 14mls of Echinacea 3x/day to a patient to have a reaction of the immune system. Immediately I argued that Echinacea was probably not the indicated remedy, maybe the patient needed propolis or astragalus, or whatever, and that what he did is use Echinacea to forcefully compel the immune system to work the way he wanted. Needless to say that remark was not received very kindly, but it helps to remind practitioners that dose (the amount of remedy given) is an important factor to take into account depending upon the outcome you want to see and the ability of the patient's physiology to deal with it.
To go back to gemmotherapy, if you have my book Dynamic Gemmotherapy, you will see that for each remedy I have given what I could find as indications in other methodologies and of course also in homeopathy....as you wrote, not a lot available but the more you will potentise, the more the risk is to lose the clinical indication of gemmos and to get into a terra incognita of an unproven remedy, although you could "guess" some of the effects using the reversal of indications and actions according to Arndt-Schultz Law (hormesis).
Regarding the 2X dilution recommended by BIH, that has never been used by any of the original creators of gemmotherapy (Pol Henry, Tetau, Bergeret...) and I had epistolary fights with the then British director of BIH who was never able to tell me where he got that from....nobody, absolutely nobody uses a 2X and calls it gemmotherapy.
Hopes this answers some of your questions....
Joe.
Dr. J. Rozencwajg, NMD.
"The greatest enemy of any science is a closed mind"
www.naturamedica.co.nz