KR Cases always get my vote.
They have a number of standard trays for
SWs (no idea what a Stomfang is or its size?) ;
https://www.krmulticase.com/trays.aspx?type=L&showsets=Y&system=WH40K&army=SW&d=1
But they also do custom trays for much the same prices. I would suggest calling them as they are very helpful with this sort of thing. It is what they do after all.
You then need to choose the case for it to go in. I have primarily the card cases (8 I think?) which are cheap and robust; very handy for storage too. I also have a double backpack to hold them out of the house plus one of their Ali cases.
Their not as aesthetically pleasing as say BattleFoam or Sabol but I am very happy with them.