I also keep my gear very small and compact that way, although I have some hunger for a bigger toy I decided to have some fun trying to push it to the limit. I already had this microscope collecting dust for many years (my wife used it on university some 8 years ago during her studies). This way I managed to adopt 60x/0.85 and 100x/1.25 (oil) objectives. Picture where all parts are visible has credit to microbehunter, it is a snapshot from his linked video as I did not want to untape optics that I already made. In the attached are the pics from the build and yeast morphology sample using 100x oil. I even managed to use spring from new objective so it remains amortized. put this DIY back into default 40x body.

Also I used plastic tube spacer mounted behind the lenses to make whole thing more robust, it is marked on the parts picture. I had to make sure that the amount of tape is enough to make a tight fit into default 40x body. remodule all the optics from new objective using electric isolation tape. There is a nice microbehunter video on how to disassemble this kind of objective: This is also very simple, you need some tools however.

take apart default 40x objective, really simple, body consist of just 2 screw parts and inside is a tube module with actual optics. This semi-toy microscope has non-standard threading so I had to do the following: I want to share my way of fitting additional achromatic DIN objectives into Bresser Biolux microscope.

Bresser biolux al microscope software