The right height - to be able to play comfortably - is important, but layering turtles doesn't seem to be a good solution. Once you start doing that, there is a chance of toppling.
If you need to make the cushion higher - why not glue an extra layer of foam to it? Or, at least velcro another layer on? If you want the added layer to look nice, make a cover for it. You don't have to be able to sew to do this - you can probably concoct something "invisible" using glue, black leatherette and hockey (or electrical) tape.
Last edited by Mollbarre on Tue Mar 05, 2019 12:47 pm, edited 1 time in total.
2016 Fender CN320AS
2018 Cordoba C10 crossover
2018 Ibanez GA5TCE
...and miscellaneous bits and pieces.