I thought it would be easier just telling you how much they weighed but like you said you can guess what a lot of things weigh like the preformed tanks.
In Germany, its mostly the GLS standart package. The wight isnt interesting unless you have a bigger list (glas or sand). For most of the orders, the standart package is enough and the only smaller version is per standart post for very small products.
24h delivery may be impossible for some products or on certian days, even in germany.
the sheet that tells you the posting cost goes by weight and location e.g. England it would have a price for something of 5kilo or less then 5-10 I think and so on