The finished blocks are a bit less than seven inches, and the finished size of the individual logs is about 5/8 inch. I cut the strips 1-1/4 inches wide and used a generous 1/4-inch seam allowance. The finished blocks were all different sizes, of course, so I just used the smallest ones as the new standard size and ignored the overhang of the larger ones while sewing the seams. I purposely didn't trim the larger ones down before sewing, because it was too hard to get an even, accurate edge.
Not only is the silk not fused, but the strips are not sewn to a foundation. I seriously considered a foundation, but I wanted the wools to lie flat, with their seam allowances under the silk logs, to lessen bulk and to give the silk some extra height. The wools helped to stabilize everything. I didn't plan it, but I think the lack of more structure, and the resulting variation, gives the quilt a sense of energy it wouldn't have otherwise.
I tried to use any one tie in only two "diamonds." A few got used three times because I didn't have other ties of the right color. So, a quick calculation says I must have used about 45 ties! There are many fewer different wools, and I had a hard time coming up with enough different colors in thinner fabrics.
If you have the urge to acquire a bin or two full of used ties, I just want to add a couple of cautionary notes. The biggest surprise of this quilt project (my first one involving ties) was how much time it takes to prepare the ties for cutting. Each one had to be deconstructed by opening it up (usually, this means picking out hand stitching along the length of the tie), pulling out the interfacing, and cutting out the lining. Then they had to be hand washed. I put only a few of similar colors into the water at a time, and checked for bleeding. Quite a few ties do not have colorfast dyes, especially the reds. Any that bled excessively were tossed. Also some ties reek when wet. Toss. At this point, I checked again for worn ties (toss) and those with excessive staining (toss). There's quite a bit of attrition. The wet ties were hung on plastic hangers and air dried. Then I ironed each one, taking care to put the fabric more or less on grain---these are all essentially long, narrow strips of bias fabric.
I started out buying ties for about $1 each (some as much as $2) at thrift stores, but although at first that may seem like a bargain, it's really rather expensive, considering the rate of attrition, and that you usually have no more than a sixteenth of a yard of usable fabric from each surviving tie---and it's a skinny, not a fat, sixteenth. Now I restrict myself to whatever I find in the bins at the Dig and Save (50 cents a pound), and the very occasional "gotta have it" tie at thrift stores.
Last but certainly not least, I want to give credit to Mary Ellen Hopkins and her book A Log Cabin Notebook. The quilt on the cover, and given in full on p. 4, is the inspiration for mine. This little book is old (1991) but still very worthwhile. She really delves into log cabin variations and design, and covers the ins and outs of sewing log cabins in general. I highly recommend it.