The 'wider' stance with stabilizers the less wobble effect so using blocks under them help PLUS blocks spread the loading so stabilizer pads don't sink into ground
BUT stabilizers can only minimize trailer 'bounce' and movement
Fore/aft movement should be minimized with the proper use of wheel chocks on both sides of trailer
Level trailer side to side then using tongue jack level front to rear.
Lower front 1" below level then set rear stabilizer jacks SNUG then run front back up to level and set front stabilizers snug
Trailer bounce....that is going to happen as long as tires/suspension are still in play along with frame flex
You can minimize the bounce by using additional jacks/supports under Frame in front of or behind tires both sides suspension can not compress