Each cubic meter of Low Pressure Boiler Tank produces 10 Steam/tick which is enough to run a single Hobbyist Steam Engine at full capacity or a Commercial Steam Engine at half capacity, basically 2 MJ/t. Each cubic meter of High Pressure Boiler Tank produces 20 Steam/tick, sufficient to run a Commercial Steam Engine at full capacity or an Industrial Steam Engine at half capacity, basically 4 MJ/t.
The easiest by far is to stick the engines directly to the boiler and use the redstone conduits to transfer power. I don't see a point personally in sending steam to a tank because you simply need a lot more piping to get it all working since the golden pipes are your main limiting factor anyway. You need the same amount of pipes going to the tank as you would need to go to the engines directly.
My problem is that my power use isn't constant, sometimes I use 200+MJ / Tick (when charging my energy cells I for my quarry, or when running heavy maschinery) and other times its just keeping up with the small use of my smelters, by adding a buffer tank I don't waste steam - I've hooked up 48 Industrial Steam Engines for burst power production, but when they aren't needed I build up steam in the tank for later use...
4 liquiducts in active mode (wrench it and give it power) will pull out the required 720 steam/t.
Or you can connect 9 liquiducts in normal mode - no wrench/power needed and they will be filled by the boiler @720 steam/t. Can all be on the same side -- if there was an issue there it is gone now.
http://thermalexpansion.wikispaces.com/Liquiduct
You don't need to put the pipe into extraction mode on a boiler since it is pushing steam out.
http://thermalexpansion.wikispaces.com/Liquiduct
Gold pipes can move 40 liquid per tick.
Now the reason you're probably getting maximum pressure is because TE's wiki says that based on viscosity and pressure it will move liquid faster. In concept, you can compress steam whereas you cannot compress water/biofuel so maybe the author took this to heart. I am excited to see you have a 36HP boiler using liquiducts that are bottle necked and running engines.
Are you engines running at 100%?