How far in advance can I make jamtarts and ice cakes?

[Bouquetsofdynomite]

Got a party on Saturday and some free time right now, if I make jam tarts will they still look ok by Saturday? (Don't care what they taste like LOL)
Also, when is the earliest I can glace ice little cakes for Saturday? Will they be ok to stack with a layer of non-stick parchment between or will that spoil the icing?
Any thoughts much appreciated thanks. I get antsy about catering and tend to want as much done as possible (I even barbecued everything before guests arrived once.)

Jam tarts - doesn't matter. Make in advance. Cakes - better nearer the time and would suggest that you ice previous night or on the day (particularly as weather is improving). In my experience, when they are stacked the icing sticks to the paper and my DCs won't touch them unless they are perfect.