Twisted Shielded Pair in MWS CST v.2006

Hello, I have been trying to find an appropriate mesh for a twisted shielded pair for some time now. We need to observe the twist signatures in a TDR signal (~50mm apart p-p). I have had some success using a PBA mesh at about 17e6 mesh cells for 100mm wire. I need to double this length, but we do not have time to simulate >= 30e6 mesh cells. I have tried subgridding, but it usually crashes the computer or takes 5-6 hours to generate. Any suggestions?

p.s. How do I post the project (i.e. which files are needed?)?

Thanks,
Nate