Installing Walthers 90 ft. Turntable on Foam Base

I want to use foam sheets over plywood for my layout base.
How deep should the foam be at the turntable location (i.e. how deep
is the $40.00 Walthers turntable, excluding motors, etc.)? This dimension is not shown on any product literature.
Thanks in advance.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I want to use foam sheets over plywood for my layout base.
How deep should the foam be at the turntable location (i.e. how deep is the $40.00 Walthers turntable, excluding motors, etc.)? This dimension is not shown on any product literature.
Thanks in advance.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I looked at the photo of the turntable on Walthers' Web Site. It doesn't appear to be any deeper than 1" OD at the very most.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.