Savic PLaza is a good size cage, that is what I have for mhy two syrians. It sounds like you have done your homework
My syrians love flax seeds/or plant them and grow some micro greens - they nearly always nibble them up straight away and don't store them for later - really good for the fur too.
a little bit of egg every now and then, broccoli/cauliflower/ occasional spring green/kale (i find too much kale can make poos soft)
Like Cypher already said, I only give porridge/baby food to my elderly/poorly hamsters.
A great healthy treat is a whimzee.
I also give them walnuts/monkey nuts but not excessively as they can be fattening.
Have fun when you finally get your hamster.