I've seen the Merlin in person at Jetpower and it looks nice. Then the starter was missing, the thrust needed to go up more and the internals were from stainless steel for heavy duty testing. The steel parts made it feel heavy, but I was told production engine would be alot lighter. Only thing you could tell is that it is P-20 size. If it puts out the 7.7lb that they are aiming for and the weight drops to 13oz like the P-20 it will be a nice engine, but personally I would not buy an engine before they been proven to work well.
Not really on topic, but you could still choose the 30% lighter Kolibri that put's out 6lb of thrust, mount it at the back of the plane shaving another 5oz of the total as you need no thrust tube. Gas start calls for a smaller battery pack and if installed with care you will ofcause get a lighter setup. 1lb might not sound much but with this small planes it's like 15% lighter
