What is a line?

I think I am going to screen print all 5 posters. I keep changing my mind on the final media and stock because while I am experimenting and trying different things and actually testing out my ideas it changes the final outcome. 

If I am going to do halftone postcards I don't think I will get the definition on the framed scenes because they will be so small. I am still trying different Pixel radius'

Considerations

Screen size + Price

Full width repeat / A0 £6.00

Half width repeat £4.00

A1 £3.00

A2 £2.50

A3 £2.00

A4 £1.00

A5 £0.50

Spot Printing

Basic Colour printing

System 3 binder and acrylic - 70p per 100g

Metallic printing ink

System 3 binder & metallic powder - 70p per 100g

Gloss overprint

Spot varnish - £2.65 per 100g

If I were to have 10 A2 different screen printed scenes using one colour it would cost £12.50 for the screens and then however much ink I would use which currently I am unsure about.