Hi Turk,

826cm2 equates to 0.0826m2 - so you'll be looking at around 80-90g (0.862 x 1kg) of pattern coat to cover at a thickness just shy of a mm. You'll be sanding and fairing back through this so your final thickness per layer is likely to be a lot less than this.

Generally though, it will use as much as it requires, the first coat especially may draw into the MDF if it is unsealed and it is likely that you'll need to apply a few applications to achieve a flawless finish and there may still need to be some filling with body-filler between stages to ensure that you have a smooth transition between sections of MDF.

Remember that, as with all resins, temperature can have a big effect on the cure speed so if it is particularly warm where you're working, you may want to use a slightly lower catalyst ratio to slow down the reaction and to give you more working time.