Running new cable inside a standing mast on a Swan 41

I am about to install a Hella masthead tri-light with anchor light and strobe on my Swan 41/018 and I need some advice.

The mast will be standing during the installation. My plan is to use the existing 2 wires for the anchor light to pull a heavy guage (AWG 10 or 12) 4 element cable down the mast using the existing holes.

Here are my concerns:

1) I don't want the new cable to bang around inside the mast and I don't know how I can do prevent that from happening. Suggestions please.

2) I don't know how the original anchor light wires are installed. Are they run in a conduit or tied or bundled or secured in some way inside the mast, that will thwart my plans?

The existing anchor light base, VHF cable, windspeed cable and anchor light wires and mast hole can be seen in the attached photo.

All advice greatly appreciated.

Further to the above post:

The Professor informed me that the wires and cables inside the mast are run inside a conduit. The pairs of small nuts visible on the outside of the mast every few meters mark the locations of the "U" bolts that secure the conduit in place.

My next questions are:

1) What diameter is the conduit?

2) Are the navigational light wires, VHF and wind speed tranducer cables bundled together in some way that would prevent me from pulling the anchor light wires down the mast without interference? 

I ask these questions because I intend to pull 4 #10 AWG wires from the to of the mast to the base using the anchor light wires to pull them through. If I screw this up, I'll have a real problem that will be expensive to fix.

Any advice gratefully accepted.

John