My seams do sometimes do a wiggles waggal, but just recently I discovered that my Janome 10000 has a cloth guide attachment, took me 10 years to read the manual (haha). It is adjustable, and now my wiggles are less. Slower speeds do help. I learned to quilt the strip quipting method years ago, and it is hard to be slow and steady. But slow is much better at straighter seams.