I was just thinking about them, wondering if they are interesting for this forum. I would not consider them spaghettis but for sure eurowestern(let´s create mor subgenre). "Schatz im Silbersee"(meaning Treasure in the silver lake) is very enjoyable, with a cool ending. MAjor difference to most spaghettis is that there are still real good guys with high morals. Also interesting is that at least some indians are also good and a major focus is on them and even their culture.
I (and i would say at least every other guy now from 15 to 70) have seen them in my youth and also read some books.(Karl May also made interesting adventure novels that take place in the arab world). I think pierre briece (Winnetou) and Lex Barker (Old Shatterhand) were the heroes of many young guys, especially when they dressed up as cowboy and indian for playing games or for carnival.
I like the Winnetou trilogy alot. Cannot remember them too much though. They are also two german towns(Elspe and Bad Segeberg) where the stories are shown in a theater style in larger arena; this is called "Karl-MAy-Festspiele". I was there once and it is great.
I personally would say that all KArl May based movies(there are also one about the stories in the arab world) are well made western/adventure movies. They don´t come close to most spaghettis in the aspects of violence or political motives.
I just checked amazon.de and there are some box set, that seem to have english audio:
three movies: schatz im Silbersee, very good
Old surehand, dont remember that one, comments point it out as on of the weakest MAy based films
winnetou und das halblut apanatschi, dont know it, pointed out as average
if you are interested i can try to investigate a bit more into it, and i guess others in this forum know much more about it.
All movies were shot in yugoslavia and the landscape there looks very westernish.