I believe process and communicaton > tools here. I don’t know the details of your context, let me share what has helped for my situation:
- Clear and open communication with stakeholders, so you have the broader perspective on project/work priority and the big-picture for schedules and plans.
- Understanding of each team member’s skills/abilities/specialties/shortcomings. Some team members can take on more work than others AND maintain a high quality of work output.
- Being able to project out current schedule with current resources, future schedule with current resources, and the path you have to raise concerns if there are resource gaps.
- Negotiation skills when you don’t have all the people you need in all the right ‘places’ (projects) on a given day.
I used at multiple locations a spreadsheet, a whiteboard, OneNote…whatever you’d be comfortable with to understand/explain/report on current state, and be able to project future state.
I worked at a place where the annual budget for my 43 person test team was my salary. I had to ‘sell’ testing services internally to business stakeholders who held the funding decisions and directions. I had to staff to demand, no way I could put one person on a single project. Our portfolio ended up being close to 100 projects/releases in a given year. We’d allocate people for 1/2 time on 2 different projects, and communicate expectations to stakeholders. We had very good testers, so they delivered on opportunities to demonstrate value to the people who were funding their salaries. Later on it was explained to me that I was essentially running a professional services organization.