B4 Tire Choice

[MITamiya]

My friends and I have our own summer racing league on outdoor tracks we have built. Its a highlight of the summer but I need some help with my tire choice. The racing is "run what you brung," so there are 4WD vs. 2WD vs. trucks. I want to run my FT B4 this year, but the tracks are built mostly on very loose dirt/sand. I tried pin-spikes last year and they just don't give enough traction. I'm looking for the most aggressive tire available for this loose dirt/sand. Can anyone help! Thanks in advance.