Ouestor, a 45 pound recurve is definitely capable of getting clean passthroughs. The trick is to tune your bow so that the arrow leaves the bow squarely instead of at an angle. If that arrow is over or under spined, it will come out of the bow crooked, and be traveling downrange sideways. Fletching corrects the flight of the arrow, and covers this up so that it's hard to see with the naked eye.
The trick is to use "unfletched" shafting, and shoot at about a 5-15 yard distance. This will tell you if your shafts are coming out of the bow severely over or under spined.
I have found that a slightly "under spined" shaft will usually hit right where I'm looking as well as give a complete passthrough as all the shafts weight will be "stacked" into the shaft when it hits the animal. Otherwise your shafts will be whipping around in flight, and will loose a lot of momentum as the shaft enters the animal.
Two blade heads can definitely aid in penetration, but not nearly as much as a tuned arrow with adequate weight. I prefer an arrow that is somewhere in the neighborhood of 10 to 12 grains per pound of draw weight minimum. Especially with bows shooting less than 55 pounds.
For some traditional shooters wood arrows are the way to go because they are offered in so many different materials that have a wide variety of weight. For instance you can get cedar arrows that are on the lighter side of the scale, that will come in around 500-600 grains. Then you can also get Hickorys that will be somewhere around 900-1000 grains. There are other arrow types (Sitka Spruce, Douglas Fir, Lodgepole Pine, Poplar, Ash, Birch, etc. etc.) that will weigh in between the weights of Cedar and Hickory. The lighter wood shafting can be fragile, and therefore really tear into your wallet, especially if you don't craft them yourself. I can make a dozen wood shafts myself for around $30 a dozen. To have them made by someone else will usually run between $60-$150 a dozen if they are quality shafts. Carbon shafts cost me twice as much to build myself at around $60 a dozen, but they are much more economical as they last a lot longer. If you are interested in carbons, check out the new Carbonwood "V-Maxx" carbons. They weigh more than standard carbons that are intended to be shot out of compound bows.
I have also experimented with weighting carbons and aluminums with clear fish tank tubing that have yielded good results. However, if your arrows are borderline in spine, putting the tubing inside usually weakens the shaft, causing it to be underspined. If your carbons or aluminums are slightly overspined to start, you can usually get good flight with the weighted shafting.
A good cut on contact broadhead can also give you quite an advantage in getting good clean passthroughs as well. Punch type heads will cause you to lose quite a bit of your kinetic energy upon entry compared to cut on contact.
