If some parts are loose or don't fit you can change the scale by +/- 1% in the slicer to get a better fit.
For small parts I advise you to print at a very low speed and a high temperature (to reduce the pressure in the nozzle and not to have warping), personally, I printed them at 220° and 5mm/s
The parts are positioned in the optimal direction for printing.
For the base, it is recommended to print with 4 perimeters to avoid visible infill.
Post Printing
You may need to sand the areas where the pieces meet.
I also advise you to put glue to have a better solidity.