Four 40W bulbs will be 160W of total power, and yes, candelabra bulbs will be similar in light output to a standard A19 bulb. For an 8x10 room, that should be plenty of light, unless the fixture has a shade or diffuser that does not pass all of the light through.

I wanted to do the same thing on my kitchen light fixture. I'm sure an electrician would be needed to make an adjustment to raise the 'thingie' in the center up to accommodate a taller 'candle'. Your other alternative would be to change the 'ugly glass shades'. I ended up using seeded glass 'shades' in my kitchen with clear candleabra bulbs, although I know fabric shades would be much prettier. ;o)

You could inexpensively replace the shades with ones that look good with that style of bulb. They come with the socket cover that would hide the white part. Lowes/Home Depot has a few options that come with the cover. I was in store yesterday looking at replacing my shade and bought the first one in the link. The socket cover is held on by the washer you already have. Bronze Wire Industrial Geometric Vanity Light Shade French Bronze Wire Industrial Cage Pendant Light Shade

I bought a pendant light with three shades that I’d like to change for a different color. What do you call a shade like this, that is not a clip-on? I’m not sure what to search for. Thanks!