I build fires in my RF offset both ways. If I'm at a competition, I'll dump a 20# bag of Kingsford in my charcoal basket with a chimney full of lit coals on top. This takes about 45 minutes to get my 150 gallon RF smoker up to 225 or so, then I close down the intakes and start feeding it wood for the smoke. The coal base I get from the charcoal gives me a solid steady temp for around 3 hours, along with the hourly stick of wood for the smoke, which allows me to get a little shut eye.
Now at home, I'll usually just light one chimney of coals, pour them on my fire grate and spread out, then boyscout stack the firewood on top to get my fire going pretty quickly, but once it's burning and at temp (225 or so), I add 2 sticks about every 45 minutes to maintain during a cook.
It really comes down to how you want to cook, there are any number of ways to start and maintain a fire in an offset. Personally, I don't think either way will get you to temp any faster, but like icyhot stated, if your wood supply is plentiful, then go for it, if not, then charcoal is perfectly acceptable too. I do suggest investing in a good weedburner, you can use these tools to start your fires, sanitize your grates and heat up your RF plate as well, this will cut down on some of the startup time.
