I have not tried the razor blade method to clean the glass, worried about scratching, etc. What I do is when the glass is coll, I take a small amount of white ash, mix it with a little water, then use a damp paper towel, put a little ash paste on the damp towel and wipe way (some needs a little scrub). Then wipe the glass again with a clean damp paper towel - clean glass in about 2 minutes.
When loading for overnight I don't have too much of a problem with the fire running away. I make sure I have been burning for a couple hours to get the unit warm and have a small bed of coals (even just a small fire). I rake all the coals to the front (just behind the ledge with the andirons) and push the ash to the back or remove it. Then I pack 2 large splits and 1 medium split (although when colder I would image 4 might be better, my larger splits are usually 6"x6" on the end, or even a little larger). into the box. Largest split in the back behind the coals, medium in front of that, touching the coals, and othe large on top of the 2. Maybe place a 2 or 3 small pieces of kindling on the coals depending upon how hot they are and then close the door with air open to full. Usually within 10 to 15 minutes I have good flame, then close air to half. I take the dog out. When I bring her back in the wood at the front is burning well, I close the air almost all the way and go to bed. In the AM (maybe 7 hours later), the adjacent room is always at least 69 F, and there are still coals in the box. If the morning is cold then I basically repeat the evening process, but with smaller splits.
Couple of things that really seem to help me:
1) although my house is fairly large (almost 3,000 SF), and the insert is in kind of a back room all of the downstairs rooms have a very open plan, with large archways rather than door ways.
2) the front foyer is open to the second floor with a wrap-around balcony for access to all of the bedrooms and my home office
3) the insert is in a large brick fireplace, floor to ceiling brick maybe 10 feet wide, so the brick gets warm and radiates heat back
4) I seem to have a great draft, even the installers commented on this - even in the open fireplace I could light a wood match and flame practically got sucked up the chimney - with the full length liner it is even better
5) the old fireplace opening was fairly large (45" wide, 35" tall, 30" deep) and well lined with very heavy brick (it was a custom fireplace build contracted by the prior homeowner) - My installer had a custom extended surround fabricated from heavy steel. I think the large fireplace box, bricks and surround also hold a lot of heat and radiate it back
My worry is that sometimes I am not burning the unit hot enough. I still tend to manage it like the old leaky stove I grew up with, and need to control my urge to alwys be feeding the box.