Yeah, that does look kinda neat (I was about to say it looked cool, but I then realised the irony).
I agree with your calculations, but there's one that I think might end up causing some issues in future.
The resistors you've specified are 1/2 W resistors, and yet you've clearly (and correctly) stated you're pushing 1.14W from each one at max power! I suspect they might 'let out the magic smoke' in due course! In order to stay within the 0.5W rating, you'd have to limit your heater PWM duty cycle to about 30-40% which would limit the max avg power accordingly.
Personally, I'd have used a slightly different method...
Jaycar wire is marginally cheaper than your 104 * resistors. I'd also suspect it would heat up more 'evenly' along its length as opposed to just heating each individual resistor body. There would also be a lot less joints to make (104 resistors = 208 solder joints).
In order to attain about the same maximum wattage, you could cut it into 6 equal lengths of about 660mm (10.3275 ohms each) and parallel all 6 lengths across your 13.5V supply to give you a max of 120W heat.
The nichrome wire could possibly be directly attached to the bottom of the glass with some Kapton tape? (Unsure!)
The only 'difficult' part would be laying out the wire carefully (avoid shorting to itself) and laying it out to make connection of the supply as straightforward as possible (maybe positive on one side and negative on the other?)
