Thank you for uploading this tutorial. The cling film tape is a great tip. Did you make this tape yourself or can you purchase this tape from somewhere?
Make the clingfilm tape by carefully cutting a slice off of a roll of clingfilm using a fresh scalpel, If you wrap some masking tape around the clingfilm that will give you a line to work around. The straighter and neater the edge, the better it will behave in use. A shorter roll of clingfilm (e.g. 20m) will be easier to cut than a 50m roll. Take care with the scalpel, you need to cut with reasonable pressure so ensure that you're not twisting or bending the blade. mrdooslatexprimer.blog/how-to-glue-and-assemble-latex/
With 0.2mm it will tend to roll so either be patient (it will return to its original shape) or use low-tack tape on the reverse. With 0.4mm or thicker just be a bit more sparing with the solvent. Clean a couple of times rather than using too much solvent. Practice makes perfect.
If you use too much solvent it will crinkle, and for 0.25mm thick latex you can’t avoid this. For 0.4 and above, if you use just the right amount of solvent you can clean the surface with only very minor expansion. I think the blue I was using here was 0.5 thick and so if you’re careful you can avoid crinkling. If you do get crinkling you only need to wait a couple of minutes for the normal shape to resume.