I told Alaskan I would try a much larger aspheric and put one on a slide to focus set up, it works but is not convenient/comfortable or practical for adjustment and carry and not as good as simpler solutions such as existing lens and beam expanders.
Beam shaping 1st is the best way so far by far that I have used, also do you want a tight beam or tight spot at distance ?
Wider dia. lenses have a place but what testing have you done and what results do you have ?