Outlaw
There is not a gasket you have to replace when you take the head off to remove the shim.

About your boat lag, I know if you do not throw your boat out and give it a very good push it takes a while to get going. I had the same issue and Jerry D talked to me about it

I'm not James but I have his rudder.
The rudder he is selling has a lower water pick-up for better flow. It is also a break away rudder. Which basically means if you hit something with the rudder it has a plastic shear pin that will break before the rudder does. Dirtysouth just talked about how his broke away when he wrecked his boat.

When I got mine I contacted him about my order he asked me if I would like to test a new type of rudder. This one did not have the water pick-up in the rudder. Other that that from the pictures they are the same. When I received mine, I noticed that this was a very well built rudder. The rudder is machined not cast. It has a high polish with etched H20 on the rudder and there was no plastic parts. I do not have scales but feeling both seem to weigh about the same. The water pick-up was a machined bracket with a copper tube. I placed the pick up between the prop and the water inlet. This separate tube allows you to choose where the water flow is better. The extra water inlet did mean I had to drill a couple extra holes in the back of the boat, but oh well. Other than the two holes I drilled for the extra pick-up I was a straight bolt on product. If you get one that has the inlet in the rudder then it is a bolt on product.
When I put it on the water the rudder handled fine. Boat turned very well and I had no issues. The water pick up was what I then turned my attention to. I started out with the water inlet all the way down. The water stream was like I had never seen come out of the outlet. There was actually a full hard stream that arched as is came out. Water shot out about 12 to 14". I then tried it all the way up that even the inlet hole was slightly behind the transom. I still had good flow. I would say it was about the same as stock flow. I lowered it a little and the water flow was much better. I have yet to try the break away portion of the rudder feature and I hope I never do.
All in all I thought it was a very good piece of equipment and was very well made. I'm actually very impressed with the looks and build of the rudder