TORONTO — It’s an age-old question: What to do on a Saturday night? For film buyers in Toronto, however, it’s a real dilemma, as screenings of top sales titles go head-to-head tonight.

Should they go “Salmon Fishing”? Pick up some “Oranges”? Do a “Waltz”? Or is it “Rampart” they’ll watch? One thing’s for sure: They can’t do it all.

Lasse Hallstrom’s scenic British comedy “Salmon Fishing in the Yemen” (7 p.m. at Princess of Wales), starring Ewan McGregor and Emily Blunt, competes with Julian Farino’s twisted holiday comedy-drama “The Oranges” (8 p.m. at Winter Garden) with Hugh Laurie and Leighton Meester.

“Oranges” runs into Sarah Polley’s extramarital affair drama “Take This Waltz” (9:30 p.m. at Roy Thomson Hall) starring Michelle Williams and Seth Rogen, which runs alongside Oren Moverman’s corrupt cop-family drama “Rampart” (10 p.m. at Princess of Wales) featuring Woody Harrelson and an all-star ensemble.

The evening will test the mettle of three top domestic sales outfits (CAA for “Oranges,” UTA for “Salmon” and WME for “Rampart”) and a Gallic upstart new to U.S. fest sales wars (TF1 for “Waltz”).

Even with convenient centralized screening locations (Roy Thompson Hall is around the corner from Princess of Wales, and both are about 6-7 blocks from the Winter Garden), acquisitions execs will be scrambling to catch all or part of the titles.

“There are press screenings the next morning, and people are hoping that sellers will wait for everyone to see everything,” says Miramax VP acquisitions Dylan Wilcox. “I think it behooves them to, unless someone wants to take it off the table that night it screens — and then it’s going to go for a premium cost that a company might not end up wanting to have spent. I think people will wait to hear what the reviews are and what the buzz is before making their decision.”

For buyers, the timing turns potential Saturday night sales fever into a Saturday night headache. How will they juggle it?

“Not easily,” says Arianna Bocco, senior veep of acquisitions for IFC Films/Sundance Selects. “You always have to go on the script, information and cast, and what you feel might be the best fit. You just divide and conquer. We have enough people here that we’ll have people at all of the screenings.”

Not all the world premieres are a mystery: Several execs have seen edited “Rampart” footage, which played like the kind of studio genre fare a wide-release distrib might roll out, but just how commercial or arty Moverman’s sophomore film plays in full will make the difference between it landing with an Open Road or an IFC.

Distribs are prioritizing their night based on what feels like the right fit for their typical target audience. But with so many fest films playing much different than they appear on paper, the temptation to bounce in and out of screenings may be too strong to resist.

“Some of them I could go and leave early, which I’m tempted to do — I think a lot of people are going to do that,” Bocco says. “Last year on a couple of the films, you could hear the seats going up, which was very distracting. We try to be zen about it all, because it is the way it is.”