my current understanding, drawing inspiration from borg31 (20 sapim cx-ray in front, 24 sapim force in rear) is to go with 24 dt alpine iii for the rear wheel (using dt 370 track hubs and dt rr 511 rims)
dt alpine iii is a little bit heavier than sapim force but it seems to be the most comparable spoke
they're rated for e-bike use and they claim
>DT Alpine III is the spoke with the lowest weight in relation to its stabilitydt aerolite are the most comparable alternative to sapim cx-ray
they would save about 32 grams according to the dt swiss spoke calculator
the aero savings are only about 0.4 watts at 25 mph according to the link below (maybe more since alpine iii is thicker than sapim laser)
https://novemberbicycles.com/blogs/blog/from-the-vault-spoke-aerodynamicssome wheelbuilders seem to prefer non-bladed butted spokes
the bladed spokes are not recommended for e-bike use so maybe they're not quite as stiff or as durable as alpine iii
and there's a bit of a price premium
maybe it would be easier to use alpine iii on both wheels and hopefully gain some lateral stiffness and save a bit of money?
maybe it's a bit aesthetically weird to have non-bladed spokes on a radially laced front wheel?
yes i know other brands spokes can be compatible but for simplicity's sake i'm looking at dt swiss spokes right now
also sapim specifies the strength on middle section in N/mm2 but it's still not straightforward to compare them
>It is important to understand that the strength measure is not an overall strength comparison; it is a comparison of the strength of the central portion. The central portions on certain spokes are slimmer which makes them look disproportionately strong. The Strong spoke is considerably stronger than the Laser despite appearing weaker in this comparison.https://dcrwheels.co.uk/custom-wheelsets/choosing-spokes-advice/ 
