For more open pattern try cutting wad petals down by half, or choose a wad that only cups half the load of shot. Works very well in 16 gauge for me.
Examples - using Z16 BPI wads in Cheddite hulls with a modest volume powder like Green Dot or using R16 wads in huge capacity Federal game hulls with most of the standard suitable powders, you likely still need an overshot wad for good crimps. In 16 gauge Remington Game hulls I cut R16 wad petals to half height. Each of these opens up patterns significantly with good distribution.
I have also experimented with nitro card and cushion wad stack in these cartridges. One can also separate the shot load with several overshot cards to create some spread.
I have not yet had good success with the Ballistic Products x-stream spreader inserts in 16 gauge loads.
All loads that I use are from published data - Ballistic Products, Lyman or other reputable source such as Powder Manufacturer - many are listed on 16ga.com with source attribution.