I definately double all that!!!
to my opinion you'd better not go cheap and not go complex all at once, while building your projector. better take your time building it and put better stuff into it. it will come easier to you and you learnmore during the process
start blue, go analogue, learn about correction optics, and you have a decent beam. Then add galvos, DAC, software and play around with it. Then you can add a dichro and a green, then you can see what you can do with colours and your software, then add another dichro and the red and there you have it
not so simple of course, lots of learning and fun / frustration / fun cycles along the way
wellcome!