1stly, welcome Matt. Be prepared to do alot of reading (of previous RWG posts on the subject of your preference) before buying. At least, if you do, you will greatly reduce the amount of money you waste & increase the likelihood that you will be happy with your purchases (in the long term).
As to modding watches - some mod their own & others pay someone to do the work for them. It all depends on your experience/skill, financial state & emotional levels. There are 3 (main) axioms that bear memorizing in the watch collecting game -
Buy the seller before you buy the watch (or watch part). If you want it done right, do it yourself. The quality of the work is directly proportional to the investment of time, research & effort you put in before you begin.
Beyond that, do alot of research on gen sites for the watch you are interested in & then post your questions here.
Good luck &, to quote Otter, my advice is to start drinking heavily.