Only problem I can see is the ribbing being knackered by the first trout to take the fly, I had that problem with shipmans till I started using crystal flash (I think) its fine pearly woven round a fine nylon core which stops the fish shredding the rib. From the look of your spiders it will be a problem.
Never seen Krystal Flash like that, only seen it in hanks. I've had the same issues with flat tinsels over bodies like that.....
Try using less dubbing, twiswing on the the thread looser and wrapping the shank more loosely so when you do wind the rib, it bites down further into the body material. Also stretch the mirage tinsel before winding then wind as tight as you can get it. You may need to go up from small to medium tinsel as the stuff become finer when stretched. Other thing to try would be a counter rib of 10lb(ish) fluoro.
Cheers
Ben