Good morning Marie, I'm not sure that I am the right person to answer your question about the ramp. I can tell you what we did.
We have two small steps into our front door, when my husband needed the wheelchair. We bought a portable RAMp from a medical supply company in Rapid City. This salesman suggested the size and length that we would need based on the height of the stairs.
When he graduated to a PC. I had a contractor come in and build a ramp from our porch to the drive way. He built it so that they didn't look like an add-on, but like it belonged to the house. She had all the ADA requirement and was able to make the slope just right!
Great, now we are in the middle of the investigating every model for bathroom. It's funny as well a sad to think that my retirement fund is now turning into an ADA, account!
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Hope this helps a little. I am now using the ramp, since I am in a PC and it works well. Good luck...