No, I do not think the Techno Formula will plane any where near as soon as your '02 Start with a 78 cm fin.
Are you pumping the Start to get going early?
Are you pumping the fin a bit to help break your board loose and onto a plane?
What size rig are you using?
Is it a Free Race type sail or a full on formula race rig?
The added width of your Start and the ability to use a 78 cm fin most likely far
out weigh any difference in weight.
Hope this helps,