Jerry H., it IS possible to install 2 spring assists! One <FONT COLOR="ff0000">I</FONT><FONT COLOR="000000">H</FONT> spring assist and one Brinly spring assist. The <FONT COLOR="ff0000">I</FONT><FONT COLOR="000000">H</FONT> spring assist mounts on the left side. The Brinly spring assist mounts on the right side HOWEVER the Brinly requires that a rear 3 point lift be installed as it mounts to the lift bar. But seeing as the tiller also requires the rear 3 point lift and you have the tiller mounted you should be good to go.