radiant heat questions

I'm considering hyrdronic radiant heat.
1. Does tubing size matter? What effect if tubing is sized less than 1/2"?
2. Does rate of liquid through tubing matter?
3. Is there a source for DIY lightweight concrete mix? Most products seem to require a licensed or factory trained installation. I can't believe mixing and pouring this mix to be that complex. I have a small building 60-70 miles from nearest applicator. The applicator has a minimum charge of $1500 for my 450 sq ft.
4. Any alternatives to pouring a lightweight mix?
--

=================================================
Franz Fripplfrappl
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Try this web site - manuals fro do-it-yourselfers;
http://www.radiantec.com/installation-manual/index.php
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 23 Jun 2008 00:48:35 +0000, Reno wrote:

Thanks. Will do.
--

=================================================
Franz Fripplfrappl
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.