My 2Strokes and 15 watt amp all use the same sized cabinet (as seem in my photos). It works great with the 8/10 combination (or 1-12). 21 7/8″ wide, 18 1/2″ tall and 9″ deep. BTW I have a brown and cream cabinet in this style for sale (like the green and cream color scheme on my 15 watter). If anyone is interested, I can post a photo or 2. The top is cut out 11 5/8″, perfect for a 5F2a chassis. The baffle is cut for 1-12″ speaker, not holes have been drilled for the chassis. The back panel is similar to my 15 watter. Solid pine cabinet with Baltic birch baffle. It’s brand new, never used. I have a custom-sized D2F cover for it as well.
The new 30 watt, Stang-ray style amp I working on now uses the same design, scaled up slightly to allow for a 10/12 speaker combo.
Can you post a picture of the cab you have? I have a Celestion Blue 12″ 8 ohm that might sound as good as the 8/10 combination. I tried the celestion blue in my 5e3 and it just sounded to big for that amp/cab.