Hi I am new to zencart and trying to set up a few products.

The products come in 50 metre lengths
and in about 5 different colors.

i have set the attributes and prices but its not working as i want:

if they select a color which increases the price by say £2
This price increase is for 50 metres.

they then select the length.

if they select 100 metres the price is doubled ( compared to 50 mtrs )
but only £2 is added for the color. It needs to be £4 since its 100mtrs.

not confident i explained that well.

Any help greatly appreciated.