JAR-FCL 1.261(d) reads:
The MCC course shall comprise at least 25 hours of theoretical knowledge instruction and exercises and 20 hours of MCC training. Students attending an ATP integrated course may have the practical training reduced by 5 hours. Wherever possible, the MCC training should be combined with the initial type rating course on multi-pilot aeroplanes.
Since you are not 'attending an ATP integrated course' it's 20 hours.