I am no expert mechanic - so this is my personal take on this:
Very lightly torqued fasteners, like valve covers, gear oil drains, spark plugs, exhaust studs, etc. - need a very accurately ( and regularly) calibrated torque wrench....IF a torque wrench it used. Otherwise overtightening, with disastrous results, is quite possible.
The valve cover fasteners on my LIKE200i require only 6.6 ftlbs; on my Honda Forza 300 (also with the rubber bushings) they are tightened to only 7 ftlbs of torque.
A 6" or 8" ratchet and a light touch, to just "snug" these valve covers down is often a best practice.
Look at the size of the bolt, and the hardness of the metal receiving the bolt to determine your force.
This is, admittedly, a question of "touch".
The OP here has no previous experience with scooters , and possibly little confidence in his scooter mechanics.
But, I would not let just any mechanic use his torque wrench to tighten these small bolts.
With this in mind - I'd recommend that he take his new rubber seals to his scooter shop for installation.
Stig