I have asked several dealers and other campers about loading my toys. The vast majority say to never use the stabilizers to compensate for a quick weight change such as loading a 1000 # Spyder. The stabilizers are designed to only stabilize your leveled trailer in it's final spot at the park.
Yes, you can use the front trailer jack to lessen the load angle. But first, you must chock the wheels on both sides. I use X chocks which work well.
My toyhauler will not load my Spyder unless I do several things to lessen the load ramp angle. I either chock the wheels or back the hitched truck's rear tires up on a 16,000 lb rated Rhino ramp. I also have a 8" trailer step from raceramps that I center under the load ramp door. Then I use a set of 6" Kurb ramps rated at 600 pounds each, to get the front tires up quickly to clear the load ramp. It is a process derived from trial and error. Hopefully your ramp is not as steep as mine, but a Spyder is going to need some measures to clear most ramps.
2019 Coachmen Catalina 29THS
2018 GMC Sierra 1500 5.3 Max Tow