This is fairly simple.
Make any wooden weapon of your choice, imbue your mods on it. Then enhance with...
ASH you will always get 10% SSI. So if you did 30% SSI imbue, or even 25% on successful enhance you will have 35-40% SSI.
On a more random way of getting higher mods than normal on wooden imbues...
Enhance wit Heartwood: Random Property
Luck 40, Durability 50%, Lower Requirements 20%, Swing Speed Increase 10%, Lower Weight 75%, Hit Chance Increase 5%, Hit Life Leech (variable), Luck 10
Now, lets say you imbued your weapon with 50% HLL, if you are lucky you will get the extra added on! Or an extra 5% HCI, or more durability!
I found all this out by imbuing woodland armor and then enhancing with heartwood. So then I checked all other wood and wow you can add some nice mods.