Hi @ElloryJaye,
thanks for pointing me at brackets for glass beds - this indeed was a good starting point. In the meantime I designed brackets that hold the magnetic print sheet tight in place, without extending higher than the print sheet, so no nozzle collision danger. The bracket files can be found on Thingiverse. Here are a few images:
The print ssheet fits snugly at 60°C bed temperature, at room temperature it has a little room to wiggle. I have the old platform, so the files are for that. I have two print sheets, both fit/are identical in size - I hope the tolerances for new print sheets are not too large and it will fit for all…
I considered to make the brackets less solid, with holes where no material needs to be, but in the end I thought that they might help keep the corners of the bed warm when left bulky.
The brackets are quite fresh yet, no long term experiences yet, but I assume my concerns are addressed, case closed 