Penelope is a little nervous about Evie still and I've been careful about letting them interact. They have done several cage swaps for brief times (Evie is too little to live in the secondary cage with the 1in bars) and have done several short interactions on neutral territory.
The first several times Penelope started squeaking whenever Evie got close to her. Evie seems oblivious and just wants to see her best friend! I used a gloved hand to protect Penelope and ward off Evie often. Twice I tried the two girls in the main cage where I thought it might be easier since Penelope would be a bit braver on her former turf, but nervous Penelope's confidence only went high enough up to be a bit more aggressive towards Evie so I went back to neutral ground.
On day #5 Penelope started to become much more relaxed! Less squeaking and less kicking Evie away. Still mainly pretending that her little sister does not exists, but improvement! And Evie is being slightly more respectful. Evie continues to do lots of stalking, but is less intense about and easier to redirect than before.