Ward

Good Morning All,
My questions have nothing to do with Quilting but I am looking for a vintage Japan Built sewing machine. I found this board and the very interesting threads on Japan Built vintage machines, which I have read through several times. I may even start to collect some 15 clones as I find them fascinating.
I've also been learning about cleaning and oiling from this board so I hope to do my own maintenance.

The reason I am hear is my hobby is sailing and I am starting to sew some covers for my boat using Sunbrella material. I was pointed to a Kenmore 158 series machine to start and bought a Kenmore 10 158-12521 model. It has been working well but I wonder if if there is a better vintage machine for my tasks.

Here is what I am looking for:
Straight Stitch only - I was told that SS machines have the adjustment pinned so they do not go out of timing as easily as a SS/ZZ machine would when sewing tough materials.
1 amp or more motor - I will be sewing up to 6 layers of sunbrella material and need punch the punch through factor . Maybe equal to demin material?
Slow Speed - My Kenmore has a 2 belt system for speed reduction. I find that easier to sew with then the a vintage Brother SS machine or another older Kenmore machine I have tried. Both have external motors with single belt drives and they are hard to sew slowly.
Lastly, I would like a longer stitch length than the what seems to be 4mm standard that these home machines have. I did read one post where someone commented on their vintage machine as doing a very long stitch.

The alternative of course is to get a more industrial model but thought I would ask this community if they knew of a vintage machine that might meet my requirements, or most of them anyway.

Best Regards,

Ward