Now I will put in my 2 cents worth. LOL When I started scrolling 5 years ago it was with a sprial blade that came with the saw which was new. I thank back on that and I believe it was a mistake from the factory as the other 2 saws that I have both had the flat blades supplied. Any ways if you will start out with the speed low and just guide the wood or float the wood into the blade your flexing will go away. As for tension if you can move the blade back more than 1/8 inch, thighten it some more. I would start with the flat blades first until you get used to cutting stright lines,circles, curves,etc. than you can go to the sprial blades and see which one you like best. I use one about as much as the other depending on the subject and wood. But by all means have fun with this new "toy" and make lots of sawdust!!
Ervin