Hey Yve,
I noticed that you asked a similar question here: Setting column width in a table
Unfortunately the answer is the same that @AdamMoore provided:
Not at the moment, but we’re working on a client-side version of UI Kit that will have much more flexible styling and layout. You can follow this card on the roadmap.
If you need a solution immediately them Custom UI is the best option.
I’m on the team that are working on the changes that @AdamMoore has mentioned. I’m keen to understand what your preferences / expectations would be for resolving this issue.
I don’t want to lead you in an answer so I’d be keen to hear your unprompted expectations, but I can provide you some example options that we’re exploring (I should add that we’re looking at the overarching problem of layout and not just this specific problem, although it’s one we want to make easy to solve! 
)
Many thanks in advance!
Regards,
Dave