Of course I don’t know how much meetings you have to schedule, but spending 1h/day for scheduling meetings as a full-time PA doesn’t sound like a lot of time to me (? - would be interested to hear what others working in assistant roles think). Scheduling meetings and doing it well so that the person you are supporting doesn’t have to spend a lot of time on it themselves and don’t worry about, is one of the things where a PA really add value. I think there is a limit on how ‘efficient’ you can be with scheduling meetings while still making it as easy as possible for the people involved in the meeting, so I wouldn’t worry too much about spending some considerable amount of your time setting up meetings.
Besides using tools like calendly where appropriate the only other concrete piece of advice that comes to my mind is that is very useful to know the details of the preferences of the person (or people) you are scheduling meetings for, such as their prefered times for meeting, what kind of flexibility they have for other times of that’s needed/the only option due to timezones, etc.
All else equal, higher salaries almost always would lead to more candidates, but once you close to a level that is relatively competitive (eg compared to similar roles in other non-profits) and seems generally relatively fair compared to the rest of the organisation, I think other aspects of the role might become more important to candidates (eg the general work environment, how much freedom people get in the role, how much involved they can get in other aspects of the organisation if they want to, etc).