For those with the Dickinson T1000 tactical straight pull (or any T1000 model actually) a aftermarkets adjustable pistol grip is available that also allows the carriage of 4 rounds in the stock.
Its from the SHS straight pull and fits perfectly. Takes 5 minutes to swap. A video is below of what it will look like.
https://www.youtube.com/watch?v=4P48D5xWwfQ
Really recommend this item to make this shotgun more suited to you.