Hey "Credits", is this the same HF jack that you're using?
3 ton Low Profile Steel Heavy Duty Floor Jack with Rapid Pump®
If so, then I may need to pick up a longer floor jack... I've been using this jack for years on my RX7 and other cars, and its always been long & low enough to reach the X-member jacking points. Haven't used it on my '14 3S GT yet.
BTW, be careful using the wood adapter you made to get around the pinch weld problem. Even a good hardwood like oak can split without warning, which can get someone hurt or damage the car.
What I did to avoid that issue is fabricate my adapters out of 1"X1" solid aluminum stock, about 2-1/2" long, and then cut a slot through the center of it on one face that is 1/4" wide by 5/8" deep. Works fine on all the cars I have, and based on a quick test fit, looks like it will work fine on the 3S as well. The AL stock is plenty strong, but soft enough that it won't damage the car. Also easy enough to cut the slot with standard DIY tools - I cut my slots by drilling a series of overlapping holes, then cleaned it up with a Dremel cutter.