If it's a fair split it is 60/40 of the loaded miles pay with 100% of the FSC going to the side that pays for fuel and gets the 60%. Beyond that it is open to debate. Deadhead pay is usually not a lot above the actual cost of fuel and usually doesn't start until after 50-100 miles. I gave 80% of the DH pay to the 60% side to help with fuel cost and 20% to the other side. Detention and layover pay are time compensation. Time is the same for everyone. That was split 50/50. Hand load/unload, inside delivery, etc. are pay for labor. That went 100% to the drivers as they did 100% of that work. All of that and more should be spelled out in your contract with the truck owner.