The material
The choice is yours, to say the least: steel, silicone, glass, non-stick steel, exoglass, aluminum...And the choice is totally up to you, as each of these materials is well suited to oven baking, after which it's more a question of personal sensitivity.
For example, I try to limit the use of non-stick molds as much as possible, so I took my old Tefal mold that I'd had for years to the scrap yard, and replaced it with a Pyrex glass mold, which is more neutral and virtually indestructible.
Of course, you'll need to be a little more careful before baking, as unmoulding could be difficult, but if you butter the mould properly before pouring in the batter, no worries.
And if the pastry is really sticky when baked, I put a strip of baking paper on the bottom, or even on the edges, and it unmolds itself.
So it's up to you, just remember that they'll all bake very well, but the tricky part will be unmolding them.
Capacity
All "classic" cake molds have a capacity that allows them to hold a volume of batter of around 1000 ml (1 liter of batter), which is the standard capacity.But it's not just the big ones: you'll also find small molds that are often twice as small, and therefore have a capacity of 600 ml, which is handy if you want to make 2 small cakes rather than one big one.
The mold needs to be able to hold the volume of batter, but not be completely full afterwards, as the cake will almost certainly swell and rise during baking, so the edges of the mold need to be high enough to prevent it from overflowing.
This varies quite a bit from brand to brand, but you can easily check it by calculating the volume of your mold by multiplying its length x width x height in millimeters, and you'll get its volume in milliliters.
Another, quicker solution is to place your mold on a scale, tare it and fill it with water. The weight indicated will be its capacity (or volume).
Once you have the capacity of the mold, divide the value by 3 and you'll have a good estimate of the weight of batter you can pour into it.
Disposable moulds
Aluminum disposable molds of various sizes (mainly 1200 or 600) are now readily available, and are widely used by professionals.
They're practical, easy to use and, above all, they can be reused several times. Contrary to their name, it would be a real shame to throw them away when they can be washed and reused.
To sum up: whatever material you choose for your mold, baking will go smoothly, the only tricky part is unmolding, and for certain materials (glass and raw metal) you need to take care to butter the mold well, or even protect it with a sheet of baking paper.
