Hi Plum. I have the same unit and really enjoy it. I had a devil of a time not getting the wood to flare. Foil didn't work for me and I ended up using the recommended 8" cast iron pan on top of the wood tray for the wood. This fixed the issue completely. Both chips and chunks worked flawlessly.
I also highly recommend getting a good thermometer or two, the built in temperature gauge read about 25^F high. I picked up two 'Master Chef® Stainless Steel Digital BBQ Thermometer' http://www.canadiantire.ca/en/pdp/master-chef-stainless-steel-digital-bbq-thermometer-0852086p.html#.VAjuNWPvm00 (if that link doesn't work, the name is the cut 'n' paste search string) from Canadian Tire for $15 each. They weren't 'thermapen' accurate, but good enough at the price.
Mom's 70th party was last weekend and I did a 25 hour pulled pork rubbed Thur, smoked Fri 9am-Sat 10am. I immediately put in a brined 14lb turkey for later that day. Both were amazing and I had a lot of compliments.
As to your questions, I open the tank regulator full and found at around 8-15^C ambient that just couple of touches south of the middle setting had me around 230^F. Having said that, it won't be the same for you. First, Ontario is much more humid and your ambient temps are different compared to me here in Sask. On my unit, the cast-iron pan is a heat sink and you don't say if you are using water or not. Water uses a lot of energy to boil, so it's also a very effective heat-sink. You need more energy with water than without.
I keep the two bottom vents closed all the time and when I find the sweet spot just tap the top vent open or shut a touch to adjust. It works for me.
You'll figure out how much wood you want based on the smoke flavour. It will continue to smoke if you have wood until you take it out, but I've read a couple of posts here that the smoke flavour won't saturate the meat effectively after 140^F (it has to be true, I read it on the internetz, YMMV). It won't hurt the smoke all that much to open the bottom door to check if your pellets are all gone or not. (If you have a heat spike, they caught on fire.)
We did a couple of salmon fillets the other day, 230^F or so, hickory chips for an hour and cook until the meat temp was 165. It was simply the best smoked salmon I have ever tasted. Wife said, and I quote, "This is how we're doing all the fish." I just put the fillets on a foil 'tray' and drizzled oil, lemon juice, dill, salt and pepper and into the smoker they went.
In short, I love this smoker. The propane means I'll have heat...even at -25^C and it does the job. Maybe not the cleanest, maybe needing a couple of mods, but it works and works well.