I don't see any apparent way to attach the ISC cables through the top mass. 

There are four DB25 cables for ISC electrical components on the table/tele (i.e. picomotors, beam diverter, and QPDs). These are first attached to the top mass and then to the ISI table. Right now this is supposed to be done by using a standard PEEK clamp inside the top mass.

See the attached pictures, and a helpful cut-out  view drawing of the top mass from D0902163.

 In the pictures, you're looking down in a rectangular opening (or a "hole") in the top mass, and deep inside that hole there is a standard PEEK clamps tightened by thin hex head bolt. Now, we are supposed to somehow thread four DB25 cables through this hole, and then through these cable clamps, squeeze the clamps, and tighten them. The clamps are 3 inches or more down inside the hole, and you cannot access them unless you have 1/4" thick and maybe 5 inches long fingers. I even don't know if there's enough space to physically allow us to thread the DB25 heads through the top mass hole, let alone through the cable clamps. 

The only apparent possibility is to disassemble the top half of the top mass to expose the clamps, remove the clamps, thread the cables with bulky DB25 heads between the blades through the bottom half of the mass (I don't know if this is possible but let's assume it is), put the clamps on, then assemble the top half again, in-situ , and rebalance everything. That's not a real solution.

I, Corey and Stefan searched for a threaded hole or two on the top mass so we can attach some hold-down cable clamps, but couldn't find any. All threaded holes are already used by something else. And even if there is one, we cannot simply loop the cables around the mass, as now the table cloth encircles the mass completely, unlike the old design.

Someone please give me a procedure to make this work.

FYI, the old way to do this (i.e. at LHO EY): The cables are first fixed to the bottom of the top mass which has a cable clamp (e.g. see this picture of TMSY top mass taken from the bottom), then the cables are looped around the back side of the top mass like this picture, then attached to the top of the top mass which has the same clamp as the bottom, and then from the mass to the ISI table.

It was really clumsy to work with, so the ISC group requested an improvement together with other things, but until today I didn't appreciate that the mass structure was completely redesigned (as opposed to small changes here and there).