@TheGecko and
@DKing it seems the trend is full replacement of the water with GM. Not sure how well that would work in hp, but thinking for me, the best option would be to use whole gm powder equal to what would be needed to reconstitute the amount of liquid in the recipe. Does that sound about right? I add my milks after cooking to prevent curdling and browning.
Even when you use liquid GM, you don't have to do a full water replacement. As one of those soapers who uses master-batch lye solution, I rarely do full water replacement for any soap. If I do, it requires mixing up a new batch of lye solution, which I'd rather not. So what I have done when I wanted more than just a few grams of added GM, is I'd buy concentrated GM in a can and add that for the extra water needed to get my lye concentration up to the desired amount. But I don't add it to the lye solution. I add it to the oils first, before other additives and before mixing in the lye solution.
I don't make GM soap very often, but I do also have some GM powder, which again, gets mixed into the oils.
I have only made it HP once, and I don't even recall how I added it; I think toward the end.
To answer your question about does it produce a better soap? Not IMO, at least for me personally, but some folks love it, so who can discount that? Not I.
I don't have goats, don't like the smell of their milk, and therefore have only used the canned and powdered. Perhaps fresh goats milk is better (for smell as a drink and for use in soap), but I've never tried fresh.
I do love goat milk cheese, however, so maybe it's not really the smell of the goat's milk that I don't like, but the smell of the canned goats milk that I don't like.