The more eyes the better and this seems to be the recommendation:
If an adult or child can still cough, cry or speak clearly, then they are still able to clear the obstruction themselves. Get them to lean forward while encouraging them to cough forcefully.
If the person goes quiet, cannot speak or cry, or can only weakly cough, you want to start with five strong back blows first. With the person bent forward at their hips, deliver firm glancing blows between their shoulder blades using the heel of your hand up to five times.
If the obstruction does not clear, switch to abdominal thrusts. Continue alternating five back blows and five abdominal thrusts until the obstruction is cleared or the person becomes unconscious.
I'm still looking for what to do if I'm alone and something happens.
The article also uses the text "In the updated guidelines, our Canadian study was cited to inform this critical change, and was the only study directly comparing different choking techniques." to link here:
https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/adult-basic-life-support
But I see no mention of any of these directions there. If someone does, let me know where I'm scanning over.
Edit: Failing at adding an underline to signal the actual link while having the URL readable.
Edit: Added the preceding "then they are still able to clear the obstruction themselves" paragraph that I'd mostly scanned over when reading the article