Thanks. I covered the wedge and blocks in heat stop paste when I fitted the ribs. I had filed them flat so that any movement should have been very obvious. I also bound them in place with wire. My concern is that the additional weight of the ribs might change the point of impact. I hope not and have my fingers crossed. The foresight will be fitted in the next couple of days and filing in the sights will show how things are.

Regards