Take note of the gunson saying to use low pressure and not full tyre pressure, I've seen master cylinders ruined due to using 30psi.

Take note of the gunson saying to use low pressure and not full tyre pressure, I've seen master cylinders ruined due to using 30psi.

Specifically, make sure the pressure of the source is below 14.7PSI when you start.

i generally use the spare wheel running around 20psi as stated on the side of the bottle in the kit, had no issues so far

I use the bleed kit at around 20-25psi using the spare wheel without a problem. On a previous car I forgot to reduce the pressure in the spare before using it and it blew all the soft hoses off where they join the hard pipes. Brake fluid everywhere followed by a frantic clean before it ruined the paint work. After reconnecting the pipes and a much longer (and careful bleed) all was fine with no further damage.