Always 2-column, 66% size bag window, nightfall skinned

[Dadditude]

I want a bag window that is always 2 columns and always fills vertically, skinned to match the fetish nightfall 66% bags. The 66% size requirement is necessary so as to allow even 36-slot bags (should I ever luck out enough to get one (or more)) to easily fit onscreen.

Examples:

4-slot bag

+-+-+
|1|3|
+-+-+
|2|4|
+-+-+

6-slot bag

+-+-+
|1|4|
+-+-+
|2|5|
+-+-+
|3|6|
+-+-+

11-slot bag

+--+--+
| 1| 7|
+--+--+
| 2| 8|
+--+--+
| 3| 9|
+--+--+
| 4|10|
+--+--+
| 5|11|
+--+--+
| 6|  |
+--+--+

etc.