Just a hint, if and when a car overflows or whatever, push the accelerator to the floor and keep it there and keep turning the starter until it starts. When the throttle plates are fully open there's no vacuum to pull fuel through the carb, and as soon as the extra fuel from the accpumps clears (2-3 seconds), it'll start. I've started a few Panteras like that for people in Modena and also a vintage Thunderbird standing in the middle of an intersection, with a worried pensioner behind the wheel...
About your problem, if you look at the link below and take the time to do each step, it may help:
http://www.tuningmadeeasy.com/...a-carburetor-part-1/
How stock is your engine? A 750DP is too much carb for a stock'ish engine IMHO.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.