Best "fit and forget" filter for 85mm f1.4g ??

Guys,

About to pull the trigger on one of these (new).

I always like to fit a screw in filter to all my lenses mainly to protect the front element.........and usually I would use a Hoya 1B or similar - however in order to preserve the "warmth" of this lens - what does everyone think would be the best filter to fit to the 85mm and leave on there?? Interested in experiences of other owners....

Thanks!