You're definitely looking at a long term/high(read very high) expense. Budget out the parts and prices, then compare that to the purchase of a gen. See which one YOU think will work better for you in the long run. I have not seen any 3035 movements for less than $1000 that did not require labor and service, and even at that, you'd still want any movement serviced before you pop it in your project.
If you have most of the parts and you want a watch that is uniquely yours and it is something special to you, go for it man. It will be nice. However, if you just want a nice tool watch that you can wear on special occasions and still have a 666, then be patient and get the gen, then service it (make sure you keep the dial,hands and other things intact) It is a tough choice, but if you have the money and time.....
E