Bleed Nipples - Stripped Threads

[number2301 1 1 Cars]

Tried to bleed my brakes today and destroyed the threads on a brand new bleed nipple in a brand new caliper when tightening it back up so I've been looking at these two threads -

 

http://forum.205gtidrivers.com/index.php?s...ic=87725&hl

 

http://forum.205gtidrivers.com/index.php?s...ic=91984&hl

 

You can get either stainless or standard nipples from Ebay or the site listed in one of those threads, but which would be best? I've got normal copper slip but someone mentioned a type specifically for stainless steel? Does that matter?

 

Finally, the calipers I replaced had 8mm bleed nipples which was great cause I've got an 8mm spanner but the replacement calipers have got 7mm nipples. Is it possible to get bleed nipples which will fit the calipers but which have an 8mm fitting?