I used the MakerWorld Make My Vase app and created this. Super easy, but I made it for the BRICKBUILDING bouquet set (10280). Printed on X1C with the white Bambu PLA Matte filament.
It measures 217mm tall (8.5" inches) by 131mm (~5 inches) width with a 90mm (3.5" inches) opening at the top. It fits them really well and allows them to stay up enough, but lay out as well. This should also work for the roses set.
Powered by Make My Vase from MakerWorld (makerworld.com/makerlab/makeMyVase)