When I do two compressors I just use one Stinger 80 amp relay. They are $20.
A solenoid needs to be rated for constant duty to handle compressors. Most starter solenoids people use are not, which is why some of them last a while and some don't. I thought about using a constant duty solenoid, but after pricing them out, they where like $45 and up. Wasn't worth the price to me since I could do it with a relay that cost half as much.
I run 2 380's , controlled by Air Lifts Auto Pilot, use 2 -30amp relays each fused @ a distribution block. Never had a problem with! The Auto Pilot is powered @ all times, & fused & straight from the battery,due to a memory.