I'm still a little confused as to why you would choose LP over HP steel tanks?
Standard working pressure of an LP steel tank is around 2400 psi.
It's easy to get a fill to that pressure, and beyond, giving you more breathing gas for your dive.
Lots of people love the LP's because they like to over fill them and carry lots of gas.
It's early, so forgive my math if anything is off, but this will give you an example of what we're talking about:
Take an LP 95, rated for 2400 psi.
Fill it to 3000 psi., and you are now carrying almost 119 cu ft. of gas... quite a difference!
With an HP tank, to get a complete fill, the tank needs to be at 3400 to 3500 psi (depending on the brand and age). HP tanks get a little hotter when being filled, so after they cool, they often need to be topped off, just to get the rated volume.
To illustrate, with my HP 100's, if they are only filled to 3000 psi, that gives me about 87 cu ft of gas.
So, even if I get a "short fill," it's still more than I get with an AL 80, and I don't suffer the bouyancey issues caused by an AL tank.
Generally, the LP tanks are bigger and heavier than I want to deal with. Yes, the walls are thinner on the LP tanks, but the tanks are larger because they are rated for lower working pressures.
It all comes down to personal preference, really.