The trick is that you're using just under 3kg of drag at Strike, it might be difficult for the 50W drag to work properly at that light a level. But try it with the line you have on there. 

Despite what others have said, the mass of the spool does contribute to inertia, but no more than the inertia (resistance to acceleration) of the drag itself. The inertia of the drag itself is why you could be onto a winner. The larger the spool diameter helps to smooth drag inertia, minimising any bumps and lumps you might still have. Hope that makes sense, hard to explain why. 

I've heard of guys and gals fishing 1 and 2kg using tld 25s and such for similar reasons.