**Core Assumptions:**  
1. **Role Clarity:** Distinct roles of Senior Architect and Engineering Manager exist, leading to different allocations of focus.
2. **Team Composition:** The team comprises both highly skilled engineers and support staff, allowing division of labor and collaboration on tasks.
3. **Organizational Needs:** The organization values both technical excellence and strong leadership for team effectiveness and productivity.
4. **Evolution of Roles:** As technology and teams evolve, so too must the balance of technical and people management skills.

**Key Arguments:**

1. **Senior Architect Role:**
   - **Technical Skills Focus: 70%**  
     - Senior Architects must maintain an in-depth knowledge of the systems architecture, modern technologies, and industry best practices to make informed decisions that impact system design and scalability.
     - Technical leadership is crucial in guiding architectural decisions, ensuring code quality, and advising on technological choices.
   - **People Management Focus: 30%**  
     - While technical expertise remains paramount, Senior Architects must also cultivate relationships with other teams (e.g., DevOps, Product) and mentor junior engineers.
     - Strong communication skills aid in articulating complex technical concepts to non-technical stakeholders, facilitating better collaboration.

2. **Engineering Manager Role:**
   - **Technical Skills Focus: 40%**   
     - Engineering Managers should possess strong technical insights to make informed decisions regarding team capabilities, project scoping, and addressing technical challenges effectively.
     - They need to remain relevant by understanding the latest technology trends and evaluating potential impacts on their teams.
   - **People Management Focus: 60%**  
     - A significant portion of the Engineering Manager's role should focus on team leadership, performance management, and fostering a positive team culture to ensure high engagement and retention.
     - The ability to mentor, develop career paths, and resolve interpersonal conflicts is essential for building a cohesive team that can perform optimally.

**Risks & Trade-offs:**

1. **For Senior Architects:**
   - Overemphasis on technical skills could lead to disengagement from team dynamics, potentially leading to lower morale and collaboration issues.
   - Insufficient focus on people skills may create gaps in mentorship and knowledge transfer, possibly resulting in knowledge silos.

2. **For Engineering Managers:**
   - Spending too much time on people management at the expense of technical skills could lead to poor technical decisions, as managers may not fully grasp architectural implications.
   - Lack of technical insight may diminish credibility with the engineering team, impacting their ability to influence engineering practices and methodologies.

**Initial Conclusion:**
Balancing technical and people management skills is critical for both Senior Architects and Engineering Managers to thrive in their roles. The proposed allocations of 70% Technical / 30% People for Senior Architects and 40% Technical / 60% People for Engineering Managers serve as guiding principles that recognize the unique demands of each role while ensuring effective collaboration, technological relevance, and team cohesion. These splits can be adjusted based on evolving team needs and organizational changes, but maintaining a clear focus on both aspects will foster a more resilient and high-performing team.