I came across this new 660nm LED while looking at new products on Mouser, it uses a standard 3535 footprint while the SST-20DR uses a 3535 with pads closer together, they work on standard 3535 kind of like Osram 3030 footprint but it’s a bit finicky, Simon for example doesn’t want to solder them onto standard 3535.
No radian flux specs, only PPF (it’s an horticulture LED), typical 5.82umol/s at 700mA 25° vs 4.82 in the same conditions for the SST-20DR bin X (870-910mW, Convoy bin is Y : 910-950), although that’s going to depend on the flux bin and unfortunately it’s not in the part number…
Should be available in a couple of day from Mouser