startpacking

I am considering a trip to Panama and El Salvador, I would arrive in each country by air. My current passport is nearly full and I have some travel booked before my planned trip to Panama and El Salvador. Realistically, once I return from my first trip, I will have one full blank page (or maybe even half a blank page left in my passport). I will only be home for about a week; so I will not be able to get a new passport (I have a Canadian passport and I can't just add pages like some countries do). My questions:-

How large are the Panama and El Salvador entry stamps? Do the countries stamp on entry and on exit (all the Central American countries I have been to have only stamped passports when I entered the country). I will only enter each country once.

Any information will be appreciated, I need to organize my schedule and the only thing stopping me from buying my airline ticket is the lack of space in my passport. Going at a later date isn't an option for now, as I have commitments at home.