they mostly crack along the notch that fits into the mounting holder on the car.

To prevent this on your new bottle, take some weatherstripping tape of appropriate width and tape to the "ears" of the washer bottle holder. That'll cushion the bottle and keep it from cracking. Haven't cracked a bottle in 15 or so years since I did that.

cheers
mike
_________________
'69 Nevada sunroof--"Wolfgang"--bought new
'73 Sahara sunroof-- "Ludwig"--mine since '78
'87 eta E30 coupe--"Johannes"
+ Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette)...
and Kermit, the Bugeye Sprite