Gunner, you will find two trains of thought on this subject. In my opinion both are correct. The axle manufacturer wants you to lift on the frame of the trailer because so many fools have used their jacks in the middle of the trailer, dead in the middle of the axle. Obviously this is too much weight for the axle and it bends in the middle. General consensus is to place your bottle jack or floor jack as close to the bracket holding the spring as possible. Actually touching it is best. The jacking of your trailer on the frame would be placing the jack just as close to the front axle as possible, actually touching the frame to start. Remember to shim this bottle jack as far as possible. Travel will be less than 8" so you will have a long way to go. Keep in mind that there are also many good ways other than these two to get that darned wheel off the ground. Other members are sure to chime in and tell you about them.
Jim in Memphis
Wife of 49 years is Brenda
2019 F450 6.7 Powerstroke
2017 Mobile Suites 40RSSA
2015 26TBUD Salem Forest River (For Alaska Trip)
2001 Road king w/matching Harley sidecar