As you know there are no lap bars.
However, The seat space, front to back isn't very big. It's a very snug fit for some people. The seat back in front of you isn't going to let you go any where....
Warning.... The weight placement of people in the log can determine how wet you might get. As well as where you sit in the log.
I prefer not to get too wet. I'll sit in 4,5,6.
You get in from the right side and exit to the left. Here are a couple of pic's from our trip a few weeks ago.
I found these photos from 2009 that "webmastercorey" has in the gallery.
As others have said, no lapbars at Splash DL. At WDW the seating is side-by-side. At DL it is all in a row with handholds on each side. So a lap bar would not have the same impact.
My daughter doesn't like the big drops either and she prefers the Disneyland version because she feels more secure behind the vertical seat backer plus I don't think she can see as well when we take the final drop. Hope that helps.