Gently pulled out connector of old battery, then pressed and held the power switch for 1 minute. Unscrewed and removed the old battery. Pressed and held power switch for 1 minute again. I know from previous work that this helps drain charge from spontaneous recharging as the dielectric recovers. Gently “fine tuned” leads from new battery to connector till connector stuck out at right angle to the edge of battery. Held the battery by the edges and let the connector slide into the socket. Set the battery down and put the screws in all the way. Then checked that the connector was completely seated before tightening the screws. The laptop come on immediately and showed 98% charge and registered normal (checked in “About this Mac”. Very happy to this point. Now for calibration.