Yo Dave, The only way I would burn locust for cooking is for an offset cooker. Even with the offset, I would burn the locust wood down to coals before I placing them in the fire box.
The reason for this is, the wood does not smell good when it burns. This is probably one of the reasons you will not find locust on any list of a suitable BBQing wood.
Here in Missouri, we have two types of locust, honey and black. The honey locust is thorny variety that you have. Black locust does have some thorns to it, but they are not near as long at the honey locust thorns. The black locust is the variety that grows the large pods that contain seeds.
I used to heat my house with wood and I burned a LOT of honey locust. Locust does burn hot, almost as hot as hedge. (Other names for hedge include: Osage orange or Bois D'arc.) One thing to remember when cutting down a honey locust tree, you need to wear good thick soled boots and heavy leather gloves. Those thorns hurt and puncture wounds can easily become infected. My grandpa said the tips of the thorns has poison in them, but I cannot verify that story.
The most important thing about cutting up honey locust is to keep the truck far away from the trees you are working on. I know it is a hassle to haul the dethorned wood to the truck, but it beats having flat tires. Those thorns are notorious for finding tires.
Beers to you,