Glass items are insured for loss by Canada Post. They are not insured for damage. Since your problem is lost packages, why not use their insurance?
Most of my shipments fall under Light Packages and they are shipped Air Mail. There is no insurance offered. If I choose Small Packages, Air Mail there is insurance for loss up to $100 ... but...it is more than 3 times the price. (Small Packages surface is more than 2 times the cost which equals more customers complaints of slow delivery) If I send out, lets say, 200 per month, it would cost $800 more per month. I'd pay that and still get only coverage for loss and not damage. I'd not get full benefit. Also, have you tried to collect from Canada Post? In my past experience, it is not worth the extra money or effort for no satisfaction or resolution.