Hi Maria,
Are you saying to need to attach the miniscope in a completely dark space? If so, that will be a little challenging to place it consistently every time. If possible, will you be able to attach the scope in a bright place then transfer the animal into the testing environment?
In terms of tricks to attach the scope, in our lab, we normally use the non-dominant hand to hold the baseplate (index finger and thumb), and then the dominant hand to grab the scope and attach it to the baseplate. Once in, let go of the baseplate, and use the non-dominant hand to grab the whole scope with slight pressure to hold the scope in place. Lastly, use your dominant hand to grab the screwdriver and tighten the scope in place. When it comes to the super-aggressive animal, we sometimes have 2 people, 1 shape their hand like a cone shape and fix the animal in there with one a part of head out of the hand. The other one is in charge of the attach the scope and tightening it in place.
Best,
Susie