Amen. I'm not familiar with sources for trailers in Canada. Perhaps dkirsop is the better person to ask on that account. Main thing is a trailer should be rated to carry weight of the boat, which for an Albin 25 is somewhere around 2,000 kg give or take. So I'd say minimum 6,000 lb/2,700 kg combined gross weight rating of boat+trailer. Next choice is between aluminum or galvanized steel. I'd avoid painted steel unless you're strictly fresh water and especially if you're launching & recovering frequently in salt water. Aluminum can be a good choice, but in my case I've had to deal with issues of metal fatigue & weld failures on my now 21 years old trailer. If I had it to do over & had to pick my own trailer rather than what I inherited from previous owners I'd go with galvanized. Rollers vs bunks is a matter of personal choice, but bulk of the weight of the boat should be primarily supported by the keel, either resting on cross member rollers or a board. Tongue length should be long enough that the boat can be floated off without backing the truck too far into the water, and/or the bunks or rollers should be such that it could be launched & recovered with a crane or Travelift.I am going to have to ask you about trailer choice next, be warned. I am beginning to think that I am very unlikely to find an A25 with a trailer.
With my previous wing keel sailboat it sat so high on the trailer that we had to "strap launch" since it didn't have a tongue extension. Even with the 14 foot strap we had to roll the trailer so far in the back wheels of the truck were at water's edge. The procedure there was 1) back down to the edge of the water, 2) stop & chock the trailer wheels & unhook the trailer, 3) attach a 14 ft tow strap between truck & trailer, 4) pull the truck forward to take up the slack on the tow strap & take pressure off the wheel chocks, 5)pull the chocks & let the trailer back down (the trailer had a set of fixed dolly wheels that kept it from fish tailing) enough for the boat to float off, 6) pull the trailer back out of the water, reverse the procedure to remove the strap & re-attach the hitch, and 7)take the truck & trailer back to the parking lot.
Try strap launching this baby sometime! Not to mention stepping and un-stepping the mast. Note that the water line was nearly 4 feet above ground & the short distance from the bow of the boat to the trailer hitch. That's why we now have an Albin 25. This is the boat we harbor hopped up from San Diego to Los Angeles & out to Catalina Island. I digress a bit, but on the 2012 harbor hop run we saw dolphins swim right up to our boat, one even swam under us. When we bought that boat in 2008 the painted trailer looked like this (modeled by my lovely Admiral). All the while we owned this boat & sailed on our home lake we kept it stored in this space at the mast up storage lot next to the ramp, launching & recovering each and every time we went sailing. The choice was between paying $87 a month for dry storage or $360 a month for a wet slip in the marina. That year we put the boat in a slip in Chula Vista, CA on San Diego Bay for the summer (we had hauled the 8,300 lb boat+trailer the 360 miles to San Deigo with a 1/2 ton Chevy Tahoe SUV) & brought the trailer home to work on refurbishing it on weekends when we weren't on the boat. At the time we lived in a house where I could park it at home to work on and a shop that had a 220V large tank air compressor. I personally sand blasted every square inch of the trailer down to bare metal & primed & repainted it. When finished it looked like this. Goes without saying a trailer for an A25 should be at least tandem axle, and I'd go with load range E tires even if you could get away with D range. It wouldn't matter for a yard trailer where distance trailering isn't a factor, but for highway use my theory is that one tire should be rated to handle one half the weight of the trailer (less the tongue weight) in case one tire fails the other has to carry the weight of that side of the trailer. At least with a boat trailer, unlike an RV trailer, you can see the wheels in your rear view mirror & know right off when one goes flat or blows out. Losing both tires on one side at highway speed could be disastrous. I favour disc brakes over drums, and if you can afford it electrically operated hydraulic brakes, aka "electric over hydraulic". Surge brakes are OK for the most part, but electric/hydraulic would be better.