If your crank case and boot vacuum tested well during assembly and assuming fuel is fresh, then your hard start when hot could be a carb or carb adjustment, fuel line or fuel vent. The Repair Specialist is quite boring but offer an excellent 101 to understanding small engine operations:
https://www.youtube.com/user/TheRepairSpecialist/search?query=difficult+start
FYI, I posted a melted boot a while ago, but regardless of the melting at the cylinder, there was no leak ... just deformation.
My pre-Huztl Kit initially bounces around while idling on the ground, but handles fine when in the hand, wasn't jarring or anything. Its a small saw after all. Now after 20 plus tanks, it is bouncing less. Maybe you can describe the vibration a little better and hopefully someone can come up with a solution. Think Ketchup has the right idea, recheck your saw for assembly inconsistencies first.
+1 on sealant with the boot. I use Loctite 718 for all my chainsaw boots. Although not required, it definitely helps to take a boot leak problem out of the equation.