I have an older Bernina 1630 and have both the wide hole and single hole stitch plates - I love using the straight stitch plate - use it every time I piece or when using finicky fabric. I agree that it was well worth the investment
There is a technique that you can use if you are having trouble at the beginning of sewing with fabric bunching, thread pulling or if the fabric edge is being pulled into the feed dogs. - can be used also if your first few stitches on the end are not staying straight and are pulling
The remedy is to use a small scrap of fabric as a "leader"
1) you straight stitch across your scrap first before you begin your block
2) when you get to the edge of the scrap fabric (leader) place your fabric pieces of your block with a small space next to the leader and sew off the leader edge onto your block without stopping - similar to chain piecing - the fabric will stitch over the feed dogs from the leader and continue on to your block pieces without any problems and you just snip off the leader scrap fabric
- when you do this the beginning stress/tension of stitching is on the fabric scrap and not on your pieces - if doing triangles or very small pieces they will not bunch up or be pulled down into the hole
- hope I explained this ok - the beginning of this video shows using a leader
https://www.youtube.com/watch?v=nTBPjlm1_44