HI

If the cap weighes in at 11lbs then your Moki 1.50 will be plenty of power. My extra 300 is just under 14lbs and it hover and does tork rolls without any problem with the OS 1.60 FX in it not completely broken in yet.
Have fun flying with it.

One quick note using bigger engines then recommended by the manufacturer is not always a good idea as sometimes it causes extra stress and strain on the structure which eventually reduces the life span of the plane. What is the horse power of your Moki 1.50