Les,
as far as I can tell, all struts are round.
Here is the general arrangement drawing I made, some details are missing in some views, and I modified the PE part for the struts you asked to be printeable for your model, this is the second pdf (scaling bars are cm).
I couldn't find any photo of this area which shows these in all detail, but I think I figured them out the right way. Take care, some pics available at NASA sites show a test model, which has two more struts reaching towards the HGA-side of the spacecraft bus.
Here are some pics of my finished model, probably they can help, too:
finished Pioneer 10 11 pictures by Herr_Bpunkt - Photobucket
Probably I should do a paper model of this too...
Thorsten