Shell doesn't stop -1 shots, only -6 shots. Poison stop -1 shots and is a lot cheaper than the cost of shots. Also poison will fire back a poison shot (Unless your damage exceeds the poison I think) with the ability to set a sysvar to 0 for a time (.shoot is a popular sysvar to use for poison)
Appart from that being small would cause the oponent to miss a lot, so a small oponent with lots of energy would probably cause the bot to spend all it's energy on missed shots.
Generaly moving oponents will be harder to hit, and if you want to be sure to hit your oponent before firing you need to get pretty close, which gives your oponent time to attack you first (Possibly with venom causing you to fire -2 shots, which would cause you to give energy instead of taking it, and for every time you hit you'll be firing even more energy at your oponent...)
So overall I wouldn't recommend spending that much energy on all shots. (You could maybe increase the nrg used to boost shots as you get closer and have better odds of hitting your oponent.)
Also damage is relative to your size, so using your oponents nrg as a reference may be overkill (Depending on your bots size).
Testing against alge probably won't give you a great picture of how your bot would work against stringer oponents.
I would recommend running it against the F3 league first, this way you'll face stronger oponents as you progress in the league. (You can download a league file and a rar file with all the bots in te league, just check the league section in the forum, and make sure you get the latest updated league files if you want all the newest league bots)
EDIT : LOL, Guess I didn't type fast enough