SUPPORT STAFF

Have you sent out letters by hand before as part of your business development or RFPs before? If you have you are aware of the thought coordination, time and sweat you need to get it done effectively. This is why you have support people to do it for you so that you can have your resources (that big brain + your time) to tackle the higher value fee earning work.
The measure of your support staff therefore is how much of your time they are able to save and not how busy they are. You would be uncomfortable having them lounge but what is their core function? To look busy or to make you most productive?
The difficulty with going with the productivity answer is that it places you directly on the spot for being productive at your firm since then the strategic high level legal work is fairly in front of you and the administrative stuff is out the way. You, my friend are without excuse.

Here's a gem: you always want to have excess capacity of your cheapest resource so your expensive resources do not spend their time doing low-value tasks. Q.E.D.