20lb. seems very susceptible to breaking with any small knick from a tooth, you may want to consider something a little sturdier, but it's do-able. Some people will tell you they finesse pike out with 8lb and have never had a break-off in their life and others will say you need tuna grade leaders with double barrel crimps and will still lose one or two each outing. I like what hank said about circle hooks, I use all circles and am always hooked right in the corner of the mouth taking teeth out of the equation for the most part. On the other hand I use all steel so I'm not concerned about break offs. I've caught my fair share of aggressive bass while fishing steel for pike.
I've never really heard of anyone targeting both species at once, usually when you go for pike, that's what you're going for. I'm assuming you want to target both so you get some flags and extra action while patiently waiting for a trophy pike?
If I had to make a suggestion I'd say go with what you're comfortable with for pike so as you don't lose a possible fish of a lifetime and if a bass hits then that's a bonus. If you really want to target bass then I'd personally make up different sets of leaders for your different applications.
There are also a ton of other factors to consider such as water clarity, what baits you are using, etc. etc. So final answer... Make tons of different leaders and fish what you are most comfortable with... After you get 40 different responses suggesting 40 completely different setups, that's just what you're going to end up doing anyway, lol. Good luck.