Mx5 nc help needed re wheel offsets

[Roccoboxer]

Just got myself an mx5 nc for a project I’m planning. I need to increase the stance of the car quite a bit and was planning on fitting some nascar style deep dish steel wheels. I was wondering if any of you guys had any experience regarding offsets to gain width. The bodywork is not an issue as the arches will be cut away to clear whatever wheels go on. (There will be a custom fibreglass body).
I was more concerned of the strain on wheel bearings etc and would like to know what I could realistically get away with without destroying the ride. The car will not be used for racing or anything of the sort but will be road legal.
Any help/advice would be much appreciated, thanks👍