I am not a fan of the look of the warehouse sprite and I was wondering if it was possible that when merging on both axis, say to a 2 x 4 size, that instead it just makes a normal chest that size?

Thanks

No, normal chest sprites can be used only for 1 wide/high merged chests. There is a "Warehouse size threshold" mod setting but it can't be set to 1, which would enable you to jump from chest sprites to trashdump sprites. But it might now work very well with such small trashdump (the fences would overlap probably).

Also there was a suggestion to use shipping containers look but the artist never answered me after the initial message.