I'm still sorting this out right now.
Here is the article that really inspired me to pursue the lights: https://meaningness.com/sad-light-lumens
And here is an article that talks about the science and engineering of mimicking sunlight: https://optimizeyourbiology.com/how-to-mimic-sunlight
From the same site, a database of all available pre-built SAD lamps: https://optimizeyourbiology.com/light-therapy-lamp-database
From that site, there are really only two lamps that achieve the requisite number of lumens, and given their cost and general availability in Canada, it's better to go your own way, in my opinion.
Here are the lights that I use: https://www.amazon.ca/NS-AC110-277V-Replacement-Commercial-Industrial/dp/B0BYN6WLYK
Here's the adaptor that you need to fit E39 "mogul" lights into E26 standard sockets: https://www.amazon.ca/DiCUNO-Adapter-Medium-Maximum-Wattage/dp/B07GYL6879/131-4030122-9153055
And here are the bases that I chose: https://www.amazon.ca/Polished-Desktop-Sockets-Vintage-Holder/dp/B0CHYPYLGN
Notes
You want to place the bulbs so that you can see them peripherally, but aren't staring directly into them. The light does need to enter your eyes, and reflection causes attenuation, which diminishes the effect. Ambient lighting is important, but you also need it to go directly in your eyeballs.
Sitting closer to the bulb improves the amount of lux you'll receive. At the light level of these bulbs, I haven't needed to be that close, but I do notice better effects when I'm within a few feet.
You can substitute other bulbs, but 240/250W and '240W equivalent' bulbs are not the same; the former are much, much, much brighter. I've been warned that the 250W fanless corn bulbs can get hot, but the exterior of the bulbs I've recommended have never been warmer than 40C, which feels like a heating pad on low. Nevertheless, the interior does get hotter, and I wouldn't leave them unattended.
You can substitute multiple 100W bulbs for 240/250W bulbs, but your cost/lumen may increase.
You can also substitute other bases, but it's important that they're rated in excess of the bulb you use.
Lightbulbs are rated using a number of different measures, but generally speaking, you want to optimize for the number of lumens first (I found initial effectiveness at 25k, but dramatic benefit at 50k+).
Secondly, you want to optimize for CRI rating. The bulbs above are 80+ CRI (meaning they output a spectrum which matches that of the sun's by 80% or greater), but if you can find a higher CRI rating, that's better.
The trade-off is that CRI rating and price are directly related, in particular at higher output levels. I looked briefly at some photography equipment which could achieve 100k lumens at CRI 95+, but they were very expensive and only had an illumination angle of 55 degrees.
In terms of initial cost, you can make a start with a single bulb at $130. In my experience, there is a significant therapeutic benefit to having even one of these lights versus other mainstream light therapy options; it's better in my opinion to buy one bulb and then to add when you can, rather than waiting to make sure you have enough to buy two or more.
In terms of usage cost, you can calculate your hourly operation costs adding the total wattage of the bulbs together and multiplying by the kilowatt/hour price of your power provider. Where we live, we pay $0.17/kwH, and with two bulbs running, that's 0.5kW, so about 8.5 cents per hour of run-time.
