you will be soooo much happier with the results of welded in connectors. I looked at the link for the ones that you were considering and having installed multiple sets, I don't understand how those would go in the car. Usually the front end has a flat plate that welds to the transmission/torsion bar crossmember opposite to the front subframe rail, and the the back end has two long vertical sides, extending from the subframe box, that fit on either side of the rear subframe rail.
One other piece of advice: make sure that you have the body/frame how you want it to be forever. Use levels to make sure that the subframe rails are all level to each other before the connectors are put in place. It's really easy to lock your frame in place in a twisted shape. The reason you are putting the connector in place is to get rid of the flex in the unibody between the sub frames. If you jack it up or put it on a lift any old way you could flex the body and lock it in a twisted configuration until you cut the connectors out and fixed it.
If your welding savior has installed connectors before he can guide you to get it set up straight before welding commences. Someday when you are replacing carpet anyway and have stuff apart, you could get farther toward the USCT style by welding some metal in between the floor pan and the subframe connectors in various spots so that they are more tied to the unibody and further stiffen the car.
