Why not just use a Prop hub extender for your DA engine!
Here it is
Description and Pricing
Part Description Part #
http://www.sierragiant.com/prod32.html
Price
http://www.sierragiant.com/prod32.html
Zenoah 2", 2-1/2" & 3" Zenoah Prop Ext. $35.00
Sachs 2" Sachs Prop Ext. $35.00
3W 1/2", 1", 1-1/2", 2" 3W Prop Ext. $40.00
DA 50 1-1/4" & 1-3/4" DA Prop Ext. $40.00
ZDZ 1", 1-1/2" & 2" ZDZ Prop Ext. $40.00