Searchfunder offers DealStats, I believe, so you can search for similar sized comps (within say $3MM below your subject's revenue size and $3MM above your subject, for example) If you don't find at least 15 comparables, expand the revenue size both ways. Use only comps that have a positive SDE or EBITDA. Most comps will have SDE because some companies don't have EBITDA.. Some have EBITDA. Compare your subject company to the comps by running a regression analysis on both revenue and either SDE or EBITDA (do NOT mix the two). You will likely find that revenue is the stronger value indicator by weighting. Finally, stop worrying about multiples. They are going to be similar to prior years. Why? because when revenues adjust, so do earnings... It is more important to look at the continuation of the benefit stream, debt service coverage and whether the financial trends of the business are positive.

Back in the days when recruiting firms were primarily chasing permanent placements, I called this industry the canary in the coalmine - if the economy turns, recruiters see (and feel) it first.
So, I guess the caution is that multiples will swing wide in a downturn - the 'worst case' scenario should be intense.
That said, a lot of recruitment firms have moved to a decently healthy mix of temporary/contract employment and permanent. In a downturn, the contract piece should hold up better or even grow as firms put off hiring permanent as a hedge to the uncertainty (but according to a Bloomberg interview with a senior leader at Manpower that isn't happening right now - still labor hoarding and adding permanent net-net).
I can't speak to multiples, plus being in Canada deals price different, but I would say look at the revenue split. You may even want to attribute separate multiples as per the split between contract (ie. recurring) and permanent placement revenue. Also, on the contract side, typically the recruitment firm will carry the payroll costs, so ensure to factor a higher level of Net Working Capital if contract employment is part of the revenue model.
Good luck!