WEM API Rate Limiting During Bulk Agent Availability Sync

How should I properly to handle 429 Too Many Requests when syncing agent availability via the WEM API? Our AppFoundry integration processes bulk updates for 500 agents. We hit rate limits despite implementing exponential backoff. The endpoint is PUT /api/v2/wem/agents/availability. Is there a recommended batch size or specific header to increase throughput for premium app partners?