I took a look at those flies on the website and a few more.  They seem to be fairly low quality.  One thing I have found out is the fish on Putah seem to like fairly sparse flies.  The micro mayfly they show on their website doesn't really look like a micro mayfly.  For Putah quality is better than quantity.  If you tie your own flies you can customize patterns to see what works and what doesn't.  If you want to try a bigger fly try a size 16 hares ear emerger in the fastest water you can find.

Brian-you might try Kiene's bargain fly boxes for good Putah type patterns. They are $1ea/$12doz and first quality-just not their best sellers. However, they are typically in 16s and smaller, which fits PC. It can be hit/miss on choices, but this time of year til next spring, they add more different patterns-you just have to keep going back occasionally to see what Bill has added. I have bought patterns based on all the bugs we have in the stream and have caught fish on most of them. Re BigY, I have used their shad pattern minnow in the smallest size with success, especially in fast tail outs; they are not "pretty", but mine have held up well. It my experience on Putah so far they catch the 10"-12" fish-both natives and planters. I have had strikes from larger fish, but they they tend to be short, half hearted efforts- not like the jarring grabs the smaller ones provide.

Steve