Only Hispanic culture I know that wants an intact buck, is the ones that never had a wither.
I'm an American of Latin descent. I sell withers to alot of latinos that were used to eating any goats, bucks and does included. I've had them come back after they buy the first one, simply because of the non bucky/non -gamy taste. I then explain to them the differences in a buck and a wither.
As far as slaughtering them, we usually lay them on a table, slice the neck open under the chin area and bleed it out. It is the least stressful method for the goat, to us anyway. It's easiest if you have a table to do it on so you can pour the blood into a pot that is on the floor
( a lot of cultures make another dish by boiling the blood, some use all the organs in a soup, so if your butchering for someone else make sure to ask what they want to keep).
It used to seem cruel when we first did it, but after seeing someone shoot one and watch it suffer a lot, this seems more humane. If done properly there is very little struggling or crying on the goats part. My wife won't stick around for the first ten minutes but once it is dead she does help. It normally only takes about 30 minutes start to finish.
I like the 60-80 pound range withers the best for slaughtering. Alot of elders like them much younger like 20-30 lbs, a couple weeks old, for the soup using all the organs.