I thought I would share my first major project and since its also my first post, thank everyone for all the advice thats been posted, a credit to the information on here since all my questions were answered.
The bulldozer was from one of MakeCNC's plans and is printed on 3mm MDF. The components were modified in Cut2D so that I could fit them onto multiple 300 x 220 (I have an A4 emblaser) sheets of MDF. The top sheet was held down with double sided tape onto a sacrificial 3mm sheet. I played with a few settings for feed etc but I found that 10mm/sec at 100% and 10 passes seemed the most efficient for a cut that went right through. The majority of pieces fell straight through after the sheet was removed and the tolerance of the cut was that good that if they didn't come out square they would stick. There is also a bit of engraving on the side that was done at 10mm/sec @80
%, 1 pass. The total project to cut took about 6 hours but there are around 90 parts and maybe I can work out a better pass rate to get this down but I didn't mind.
Overall I don't know if its a credit to MakeCNC or the way the Emblaser cuts so well but everything went together with tight tolerances and Im happy.
Thanks again for everyone at Darkly for a great little machine.