>shery, it realli depends on what ur parents wan for guo da li.. cos for my mom, she ask my mil to substitute everything wif angbaos..there are shops tat sell guo da li items.. 1 in chinatown, 1 in IMM and i think there's one in Jurong west.. sometimes those traditional pastry/cake shops will be able to help oso..
as for choosing of dates, as long as the date is suitable for having customs, then shld be ok if u are not tat particular..