Snap-On PAKTY impact extension tray 1/2"

I tried to model after some pictures i found on internet. Tray is made for a 75mm, 125mm and a 250mm impact 1/2 extension.
I was having some problems rounding of a couple of edges, they are still straight. Can't figure out what to do.
If someone is able to figure it out, please help! :) If anyone needs, i can model other Snap-On trays too, but it would be easiest if you sent them by mail to me.

Extensions are modeled after Biltema Art. 71-149
(https://www.biltema.fi/en-fi/tools/hand-tools/socket-tools/heavy-duty-sockets/impact-extension-12-3-parts-2000032235?srsltid=AfmBOopiseWPKhOlB4HkP6R0Nts6GGaRrZgkdm3EgieMQzEYs2p20H_6)

I modeled the extension separately and made them a snug fit. I tried to modify them a bit bigger, i hope extensions will fit. I don't have a 3D printer, so i can't test.