I'm new in the vacuum infusion so I have a few questions.
I want to make a composite part and for the female mold I'm gonna use a fire scale diam. 80 cm. depth 14 cm. I had the idea to make a box around in formica so I have a flange to attach the vacuum bag. Can you give me some advice about the position for installing the vacuum and infusion line. Do I place the infusion connector (with or without spiral tube) in the middle of the part or on the flange? For the vacuum line, is a connector enough or better in combination with a spiral tube?

Depends on the shape and size of your part, so pictures would help. But your part is small enough that it isn't really going to matter hugely which way you do it, so don't overthink it. Rough rule of thumb if youre using 6mm feed lines is to try not to feed further than 500mm, otherwise the friction slows the resin down dramatically and your infusion can take a long time and you're more likely to get pinholes.

Easy Composites cover this quite well in their tutorial video:

https://youtu.be/qMPSIKfkdtQ