I had to purchase more stain and an oil based protective finish. In the past I have used a water based version with a Polycrylic finish, but since the windows have an oil based stain I needed the correct topcoat. Only I couldn't remember what sheen I used before. So I got semi-gloss.
Once home the error was revealed but actually compounded. Previous projects had used Satin but all the woodwork in the house appears to be Gloss. So rather than redo all the interior woodwork or sharply contrast with it, I'm sticking with the semi-gloss finish.
Current Status: Top pane - glazed, exterior painted, interior single coat of stain. Bottom Pane - glazed, exterior painted, interior stained and first layer of topcoat applied.