Matt
If you are willing to weld or braze why not do what I did. I added a steel pipe bung right at the bypass tube. This way the tip of the sensor is in the flow and gives you a good reading all the time. I just used my torch and did a gas weld. Good idea to use a couple plugs and a plate to pressure test before installing. Mine has been like this since 2004. Just an idea, but it does require some fitting and welding. I only installed the tip of the sensor into the flow about a 1/16". The sensor on the bottom is for add on gage and sensor on top is the stock gage.
http://www.sccoa.com/forums/attachment.php?attachmentid=12076&d=1112734712
Later
dbd