Thanks for your reply, very helpful. You mentioned creating my own client side projection. I tried that but I could not figure out the correct math equations. All my data is in NAD27, Spatial reference 4267 and I need to project it to WebMercator, Spatial reference 102100 to go in the map. It would be interesting to know how you figure out your own if you can share, where did you find the math equations, etc.