Good Luck with the tilt table test, Doydie. I hope it goes well for you and am SO glad you are getting the testing to hopefully find out the problem and get you feeling better
I've had 3x tilt table tests. The first showed POTS (my BP doesn't stabilise during changing positions and my heart races, causing pooling in my legs and faints). The second I had was more in depth from another hospital as they think there may be more going on. The third was a meal challenge where I had to drink a milk shake and then go on the tilt table to see if my BP and pulse changed... only lasted 5 minutes as my body couldn't handle it. Still waiting for results of those but was told on one of the tests that had to be stopped that my BP went as high as 190/140.
Not going to lie, they aren't nice but the good thing is they don't hurt

And I'm sure they'll be different for everyone

The drs would never keep you on for longer than needed.
Know what you mean about the 7:30am starts. Mine was around that time and I am NOT a morning person... usually strolling out of bed at 10am

The person doing the test told me they can sometimes get better readings in the morning so that is why the prefer to do them then.
I hope everything goes well for you. Definitely keep us posted on how everything goes