All valid points. But regarding the measurements, neither LTT or GN testing methodology are realy scientific. Those are youtubers with limited understanding of experimental design and analysis. I have never seen them do simple significance tests or try to explain the variability in the data. But I havent watched all the videos so 乁( •_• )ㄏ
3D printed stuff is not geat for hygienic reasons because the little groves accumulate dirt over time and is hard to clean. Did you coat the print somehow?