Brook's right. They'll catch. No question and I'd happily fish them.
Among people who use spiders you would get a raft of opinions on length and thickness of hackle, length of body, angle of hackle etc etc.
For what it's worth, I'd prefer the body a little shorter and the hackle a tad more sparse.
Personally, I suspect that the jay hackle is a little too soft to be ideal.
If you are interested in traditional patterns, Mike Harding's book is worth the tenner you can get it for. Mostly recipes but some instruction on tying, history and fishing included.
If they are your first spiders - well done

As for fishing them - they'll catch throughout the season on rivers - across and down or upstream. They'll also catch on stillwaters fished like a buzzer - a very slow twitch retrieve often works. A Stewarts Spider can be deadly in or just below the surface film. Snipe and Purple also does well whilst Wobbly Face on here is currently doing well with a Williams Fancy.