As a Chemical Engineer you should easily be able to calculate the resultant pressure of the Methane cylinder contents in order to find the appropriate match with available compressed gas cylinders. To find out the standarization of available compressed gas cylinders and the associated valves and relief devices, go to the CGA (Compressed Gas Association) website and order/buy their authoritative book on compressed gases titled: "Handbook of Compressed Gases". In it, you'll quickly be oriented with the criteria and the subject matter involved in compressing and bottling Methane and other gases.
Methane will at room temperature not form a liquid and you will thus need a high pressure in order to store any significant mass in a small volume such as the 0.3m³ given.
Normally at atm. pressure you can liquify methane by cooling it cryogenically. The temperature is then quite low approx -260 deg F or -160 deg C
When storing liquid methane at room temperature you do this in an open "bottle". The boil of is kept down by using an insulated vessel. The boil off that will occur anyway is collected and eiter used as fuel for a compressor and/or re-liquified.