"Where should one pitch interest rates to both keep savers and
borrowers , happy ?"
My schoolboy economics taught e that interest rates should be pitched at about 1% above inflation (so about 3%-ish at present). This gives savers a small premium in real terms for lending the banks their money (rather than see its value diminished) and sees borrowers paying a small premium for borrowing (rather than see their debts reduced due to inflation). That's the theory and it worked quite well until somebody decided that the only way the country could escape from the problem of bad debt was to provide cheap money (and thus increasing, er... bad debt).