Spare tips for a micro model sander, https://www.amazon.com/dp/B0D46TYHP7?psc=1&ref_=cm_sw_r_cp_ud_ct_Q3HTKBCFNKZJ1Y74CNQQ cheap sander that gets the job done, Tips that came with the unit are resin printed and brittle, So i decided to make some of my own, feel free to adjust to your needs. i printed them on the A1 mini as you can see in the photos with no  brim, the uploaded file includes a brim and supports, you may have to do a bit of post processing on the base depending on your print settings, Happy Printing !