Sorry, I just saw this post.

I pour thousands of sickle hooks every year for sale for the spring walleye run. I ran into similar issues with different do-it molds. As some have mentioned, if you switch over to the "lil-Nasty" hook, this will avoid the headache however, a ton of my customers only know of the word "Matzuo".

Here are a couple of things I have done to help the process. The biggest issue I have seen is that, because the gauge wire is bigger, the hook takes up more of the cavity and doesn't allow the lead to flow to the bottom. One of the biggest issues is the offset between the hook eye and the shank is slightly different. It tends to push the shank to the back of the mold. If your collars are at the back (some of mine are) you run into issues with the lead not flowing down to the collar.

To combat this, I took a drill bit slightly larger than the spot where your eye goes in the mold. I milled out both sides of the mold. This allows you to position the hook so that the shank is centered inside of the mold slot (hope that is clear).

On a few of my molds, I've had to use a dremel and ease the mold on both sides slightly to open it up and allow lead to pour. I pour a ton of 5/8, 3/4, and 1 oz jigs. Now, I actually have two molds.. one for Matzuo (that I altered) and one for regular hooks.
All of my 1/32, 1/16, and 1/8 I have switched over to "Lil-Nasty" and have had no reason to alter the mold.

Let me know if that helps or if you would like me to get a couple of photos for you to show you what I am referring to.