The ratio of base to LR
doesn't matter. All will eventually look the same in time. The only difference being the amount of time it takes for necessary organisms to colonize the base rock. It's really up to you and your budget. As long as there is some LR
introduced, you'll be just fine.
If the LR
is your main filtration source, 35-45 lbs total would be a good number. It really depends on the density.