So I assume the grommets are already installed and you are restringing. I do not recommend you use an awl since there is already a tensioned main string in the hole--the risk of breaking is too great. Instead, you should use a "string awl" that is, take a piece of scrap string--the stiffer the better, cut as fine a point as you can on the tip and use your pliers to get it in the hole from either side. Once you are able to do that, put a little wax or chapstick on the scrap string awl and work it in the hole. This should give you clearance to get your tie off string through there. Good luck.