I don't use buckets any more but instead use a python. I add a little to the tank as soon as I start the water running in and then a little more when it is full. In actuality, I am probably adding a full dose both before and after as I never measure it. Dechlor is relatively cheap so to me it's easier to just squirt it in. I don't think there is really an issue either way. If you're using buckets, I would say it's best to add it to the water in the bucket before you add it to the tank. That's what I did before I got my python.
Also, on a new tank, I would say it i extremely important to have a test kit. As mentioned, a kit costs less than $20 (the API master kit that is so popular with members here is $18.99 from Big Als' and I know they are in Canada and
here is one from another Canadian company for $24.99 Canadian) and if your tank isn't cycled, you can easily lose a lot more fish than $20 worth not to mention the money you spend on medication to treat the diseases brought on by poor water conditions (probably the number 1 trigger of diseases). It is well worth the money. And don't be fooled by theprice of strips. If you compare the number of tests per dollar, liquid is much cheaper and strips are about as accurate as sticking your finger in the water and trying to figure out how much ammonia (5-in-1 strips don't even test for ammonia which is the first toxin you will encounter in a new tank) is in the tank.
If you indeed can't get the test kits, I would suggest you only start with 2 small, hardy fish and to do 30% water changes every day for 3 weeks before adding any new fish. At least once a week during that time, you should take a water sample to your fish store and have them test the water for you (make sure they tell you the actual results and not that "they are in acceptible ranges" or something like that. And when you get right down to it, the water and trips to the fish store may be worth the money.