Why don't you just let the community do the "hard" task and let moderate the forum? Like it's kind of standard nowadays so that users just flag/report content and it will be invisible until a mod approves/removes it?
That way the mods should have much less work and users might be happier because their legit posts are actually visible and not in limbo for hours or days because only 1(?) mod actually does this job.
Relying on users to flag spam doesn't work because when you present a shitty task to a large audience everyone hopes or assumes someone else will do it, with the result that nobody does it, except for the staff/mod users (who are already doing it, and the people doing initial post approvals and the main responders to around 2/3 of the threads in the forum anyway). So it's not really any more or less work for staff, and it's a highly effective spam block. TL/DR; It works, and despite the occasional complaint (which like busses, come along in threes) it's not going to change.