Gay

Checked out those links and am wondering why they are so expensive. Pam Bono gave one away to every new subscriber, but I still haven't used mine, due to having drop-in bobbins.

sailsablazin

I also use the Angler 2 made by Pam Bono. I couldn't sew a 45 degree angle if my life depended on it and this has helped me through my last quilt with a "Buzzsaw Block".
I do have a front loading bobbin however...

newleafstitches

The Clearly Perfect Angles works with any machine and it doesn't have to be removed to access a drop-in bobbin. It just rolls out of the way and goes right back into place. There are also more markings along with an alignment key right on the product. It's more user friendly than the Sew Straight and doesn't need any repositionable tabs either. In fact, Eleanor Burns used the Clearly Perfect Angle for years before now, copying the idea.

sewbeadit

I have this product and it works great, but I think painters tape would work for you just as well! Cheaper too