Bill,
Your pre-lube device operates very similar to an Accu Sump system, so if you don't mind I'll refer to it as an "accu sump". Most folks use the sending unit port for oil take-off or for "accu sump" installations as you propose.
A better location for connection of an accu-sump however would be on the left side of the block, near the fuel pump. You'll find an allen head pipe plug. The port plugged by that pipe plug intersects the discharge of the oil pump.
I'm not convinced there is any benefit in pre-lubing the motor, but it should be obvious that such a system could cause drastic problems should it fail, so proper engineering is very important.
Your often well lubricated friend on the PIBB, George
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.