I'm building a 10' 6" surf spinning rod and when I put the handle where I like it the rod is tip heavy, not drop to the ground heavy but it goes tip heavy slowly. If I move the handle and reel up a little, about 3" it is ok, going to be a personal toy, could I add some weight to the butt to keep the handle and reel where I want it or should I move the handle and reel forward?

As long as it’s a personal toy I would try it both ways tape the guides on temporally attach the reel.
Cast it a few time each way to see how it affects casting and performance then make your design

Are you using a plate seat & cork tape? You could just move the seat to adjust the balance point until you figure out the best method for you, after fishing the rod a few times. Keep in mind when you add 300 feet of line and a 2oz plug laying on teh waters surface after a cast, most surf rods tend to be tip heavy regardless.

FOr me I prefer to move the reel seat up and deal with teh extra length than to add weight.

Another solution to consider..........sometimes I put what is called "pencil lead" inside
the blank right at the butt. Because it is in the rear a little bit goes a long way. I made up
a tool to balance the finished rod (I like it just a tad in front of the reel). Then epoxy
the lead in the blank, put on the butt cap and woila' a perfectly balanced rod to fish
all day with and not get out the Ben Gay when you get home!!

Try it......you'll like it.

John

Bigfish,
Use the method that best fits your need.
I personally like a handle of a specific length. i.e., I don't like one too short, nor one too long.
If it is too short, it doesn't handle and cast well.
If it is too long, the butt of the rod is always hitting my body when I cast.

The other thing about moving a reel forward on a rod to balance it - is that you are giving up fishing rod length.
i.e. what is the point of having a 10 foot rod, if you move the hanle up three feet to balance the rod. You are really only fishing with a 7 foot rod. i.e. the length from the reel to the tip of the rod.
Rather, I like to place the reel at the optium placement for my casting needs.
Then, I simply add butt weight to balance the rod.
I add butt weight by adding lead tape - on the OUTSIDE - of the blank, before adding the handle material.
I typically turn my handles on the blank, so I simply ream the first couple of pieces of cork that surround the lead balancing tape, and then glue up the cork as needed. When the handle is turned down, and the butt cap added, there is no sign of weight added to the rod.
Since all of the weight is concentrated in the last inch of the rod, the maximum blanace is achieved by adding the minimum amount of weight.

Take care
Roger