I have FMQd about 85 or more quilts. The first one I ever did is on our bed now. I can really see my improvement. I'm still not real good at it but it pleases me and that is all I care about. I only give quilts to people I think need a quilt. I don't do any fancy designs, just like to move to suit myself. the hardest part is learning to move the hands according to the speed of the machine. For me going fast and moving fast works best for me.
I'm with your grampa, don't borrow trouble. I set my top tension at 2, I use whichever thread I choose. Lowering the feed dogs makes it easier for me. Stitch length doesn't matter if the feed dogs are lowered. My bobbins are metal as are all the machine parts. Practice is important.