This is an old hymn that's is public domain. Gene Oh had posted somewhere about the key of A. I initially had trouble with it also and still struggle with some tunes in A. Anyway, I was playing this last night from an old hymnal. It was written in A and almost fell out of the C chromatic all by itself. It uses both C#s so it might be an easy way to get familiar with A.
I Surrender All for chromatic harmonica.
Key of A on C harmonica.
+5* +5* -5 +5* -4 -4 +4* -4
-3 -3 -5 +5* -4 +4* -3
+5* +5* -5 +5* -4 -4 +4* -4
-3 -3 -5 +5* -4 +4* -3
-7 +7* -6* +6 -5 +7* -6* +6 -5 +5*
+5* -5 -6* +6 -7 +7* +7* -6*
+6 -5 +5* -4 -3