The casters are not on the bench legs, yet; however, I did mount the scroll saw and make a cut - even if it was a poor grade of scrap plywood... Everything worked nicely with minimal vibration.
When mounting and securing any similar scroll saw that has "blind" mounting holes at the back of it, I strongly recommend marking, drilling, and securing the 2 front fasteners first. Then with a pencil draw an outline of the back of the base casting where the rear mounting holes are. Then locate them by doing a take-off of the measurements on the scroll saw and transferring these dimensions to the traced outline on the bench top. Finally drill these remaining 2 holes. If you are using a hand drill, don't expect to get perfectly perpendicular holes. Use a round wood rasp to enlarge the holes in whichever direction is needed. It's really quite easy - just takes a wee bit of time. Remember, it is best to take off just a small amount of wood with the rasp at any given time, replace the scroll saw, check to see if the holes align (I used a nail punch to push up through the bottom and move in a circular motion to move the scroll saw holes directly above the drilled holes), and either file some more or put in the bolts and tighten them up :-) How many times by trial and error is needed to get the perfect alignment? As I took off just small amounts of wood with the rasp each time, it took me 5 times putting on the scroll saw, checking, removing the scroll saw, filing the holes a wee bit, and trying again. Patience is the key word.
Now that I've decided to put on 4" diameter casters I need to take the table apart, cut the legs shorter and attach the wheels. Of course I'll have to beef up the table legs as the caster attachment plates are larger than 2- 2x4s :-( More to come.