Pemko has a minimum order requirement. Orders smaller than the required minimum have a longer lead time as we need to consolidate onto a stock order. If you need a faster lead time, simply exceed the minimum order amount.
Pemko 158D 36" Dark Bronze Anodized Aluminum Offset Threshold
I also still feel that an automatic door bottom is a very good choice especially when using the threshold that you are considering given the overall width of the threshold which is 5 and a half inch.
Keep in mind that the elegant nature of the automatic door bottom is hinged on the fact that as soon as the door opens the automatic door bottom immediately begins to snap back up into its housing getting it off of the top of the thresholds and therefore nothing dragging across the top of the threshold where as a standard door sweep is simply going to make contact constant contact with not only the threshold but potentially the floor as well.
I stick with the automatic door bottom than I do so and almost all instances.