Welcome on board
I agree with all previous comments. Firstly saying I bought mine second hand here on IIS, the only detail, that I'm not happy with my 12" Lightbridge, is the the altitude wheel handling. Even using counterweights, at high magnification doing tiny adjustments to track targets, can be challenging.
The zero magnification multi pattern red dot finder coming with your new dob is a very good one and I wouldn't consider replacing it with other zero mag finders. However, you will surely benefit from an optical finderscope.
In this case, my advice is for a straight through, than a right angle one. While the latter is more comfy to use, the first will give you a view matching the dob scope one.
Surely I advise you to get also, if you don't already have one, a decent binocular to help you identify star hopping patterns. A bino to be used in this role, should offer a wise compromise between field of view and magnification. After several experiences, I'm happy with the 11x70mm (my one is from Andrews).
As others already warned you, you may get the accessory bug and end up like me actually using both a Telrad (a cumbersome red dot finder) mounted on top of a short refractor scope (70mm, FL300mm) mounted on the dob by....
