If i buy a dozen gold tips and get their standard insert can i then buy the added weights and just screw them into the back through the shaft or is there a special insert that will allow that?

I want a 35/55 with 100 grain insert weight.

Your best choice is to get some 100 grn brass inserts.

any particular reason?

I don't glue the insert in until I'm happy with the weigh and flight. They make a tool (long allen wrench to turn them from the rear of the shaft but this way is easier and cheaper. Just use soft glue or shoot into a bag.

so you just screw them in to the standard insert, get it tuned then glue them in. Can you take them back off if you decide to change broad heads?

I'm with Badger, Buy the 100 gr brass insert

ok but please explain why... I like to know the why behind what I'm doing.

I've use both the 100 gr. inserts and the add-on weights for tuning.Get the long allen wrench so you can adjust the weights after you have installed the inserts.I like the weights because you can make small changes and have the adjustabilty to other bows and set-ups.I tune my carbons with what works best for me,whether it is 50 or 100 gr. inserts or the weight system.

The great thing about the weights is that you can put them in or take them out as desired. You can add more weights to the back of the first weights and adjust to about any weight for perfect arrow flight.
The weights are threaded and have a hex head to allow the use of the wrench.
Gold Tip has a 3' allen wrench that allows you to go in thru the nock end of the shaft, no need to remove inserts (risk damaging shaft) to add or remove weights.
The old GT system required you to remove the insert to add or remove weights. This new system using the long wrench is very easy to use.
Most of the 100 gr brass inserts are not threaded for the weights, but the standard GT inserts are threaded for the weights.

great... sounds like a winner to me. I'm not sure what weight i will really need  and have never bare shafted before so whatever will make it easier to begin with.

I use the 100 gr brass, one reason for doing so is that they are long and I feel give strength to the forward end of the arrow and also have more surface area for the glue (JB Weld) to adhere to. I like GT's.
  Regardless of what set up you use, if you will take the time to learn to bare shaft you will find it to be well worth your time. It makes a better archer out of you, and give more confidence in your equipment and yourself.      

went with the gold tips and regular insert... they just seemed to handy to pass up... Thanks BigJim

I've had several weights loosen up and rattle inside the arrow even with locktite.