1. What are the pros and cons of using a head cement such as flexament as opposed to a water based product.

2. Are there general rules for when to use hooks with a turned down eye vs straight vs turned up.

3. Relative to hackle size: if tying a fly such as a elk hair caddis, how critical is it to use #12 hackle on a #12 hook. If all one has is #10 hackle, how bad is it to use it on a #12 or #14 hook. I used the elk hair caddis as an example, but have wondered about this on other flies as well.

It seems like I am always missing something when trying to follow recipes. I either don't have the exact color or the exact size.

Thanks for any responses.