Site-directed spin labeling using two strategically placed natural histidine residues allows for the rigid attachment of paramagnetic Cu. This double histidine (dHis) motif enables extremely precise, narrow distance distributions resolved by Cu-based pulsed ESR. Furthermore, the distance measurements are easily relatable to the protein backbone-structure. The Cu ion has, till now, been introduced as a complex with the chelating agent iminodiacetic acid (IDA) to prevent unspecific binding. Recently, this method was found to have two limiting concerns that include poor selectivity towards α-helices and incomplete Cu-IDA complexation. Herein, we introduce an alternative method of dHis-Cu loading using the nitrilotriacetic acid (NTA)-Cu complex. We find that the Cu-NTA complex shows a four-fold increase in selectivity toward α-helical dHis sites. Furthermore, we show that 100% Cu-NTA complexation is achievable, enabling precise dHis loading and resulting in no free Cu in solution. We analyze the optimum dHis loading conditions using both continuous wave and pulsed ESR. We implement these findings to show increased sensitivity of the Double Electron-Electron Resonance (DEER) experiment in two different protein systems. The DEER signal is increased within the immunoglobulin binding domain of protein G (called GB1). We measure distances between a dHis site on an α-helix and dHis site either on a mid-strand or a non-hydrogen bonded edge-strand β-sheet. Finally, the DEER signal is increased twofold within two α-helix dHis sites in the enzymatic dimer glutathione S-transferase exemplifying the enhanced α-helical selectivity of Cu-NTA.