Supporting stake trees

I have 4 Sissoo trees which grow about 6 feet a year and are very brittle. Now they are 12 feet tall and have very skinny trucks because they are young and were planted about 3 months ago. Where I live there is lots of wind. So I stake them with 2 stakes apace in a V at about a 10 degree slant, they are sticking 6 feet out of the ground, and then screwed 5 foot extensions to I can tie them off higher so they don't get broken off. I put a cross pole about 5 feet above the ground between the 2 poles about a 6 inches from the top of the big poles.They do shake quite a bit with the wind so my question is the cross pole between the 2 main poles is at the right height are should they be lowered. This is an engineering question and I just don't know.
Richard
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Richard Miller wrote:

Stop watering them so much and they will grow slower. Staking trees is a bad idea. You don't need to be an engineer to grow a tree.
--

Travis in Shoreline (just North of Seattle) Washington
USDA Zone 8
  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.