Boat trailer jack

Got an EZloader 22 foot, dual axle with brakes. The axles are square. The axles mount at an angle, so the bottom of the square axle is at an angle and not parrallel to the ground. Trailer manul says "use a hydraulic jack to change tires. I have one of those little 2 ton bottle jacks, but ehn I tired to use it, I found the top of the bottle jack plunger where it takes the load is flat, and contacts the axle on on an edge, and not flat like it would it the square axle's bottom side was parrellel to the ground. Tried it anyway, and since the bottle jack punger was flat, and just met the axle on an edge, with a load on and in mid lift, the jack kicked out.

Found the jack for my Ford van, same type used in Rangers, and its a little bottle type jack by its mechanical, and works as you spin the handle to lift.
That type jact, at the top of the plunger, has a slight U shape to it, which really mated perfectly with the tipped/angled axle of the Ezloader, and under load did not kick out.

How come trailer builders don't tell you EXACTLY what make and model of jack to use with their product? Even better, why not have an accessory kit you could buy that would be the jack, and a handle for it, that would lock to the trailer. Just wondering.

PS Can't use one of those funky C-Shaped axle jack, cause my brake line run on the back of each axle, and I ain't goona squich one of them just to change a tire.