Custom Order C6 Torque Converter

I am not happy with my torque converter in my C6. It is a Transtar FM127 hi-stall converter with a 1800-2200 RPM stall.  My engine makes lots of torque and low end power, plus I have 2.75 gears, so it flashes on the high end when I get on it.  The stall speed seems good ok, and it makes for a nice launch but the issue is the torque converter it is slipping a lot at cruiser speeds  On the highway I am probably at about 15% slippage and I am above the stall speed.  I noticed my highway RPM went up significantly with this converter over my old stock Ford unit.  So I think it is just a cheap inefficient design.

I am looking at getting Jay Broader to build my a custom torque converter.  I sent him my car's specs and he says 1800 RPM stall would be good.  Is there anything I should ask for to ensure that this converter doesn't slip excessively at highway cruise?  I would think that at cruise I should be able to have 5-8% slippage with a good quality converter.