Yes me too same scenario - my house is also in Main road and even 5 minutes of parking will lead to entire dust in the Bike....
See its all New Bike Syndrome.....
I too had problems like you when i bought my babe
But One year Down the lane.....Now i never Wash her or even temp to Dust her.....
Bikes are Tempt to get scratches - infact they are not Household things to keep it Perfect Scratchless....
They are Roadside warriors and scratches and marks are Common....
So do not worry.....
I can give you a best option....
Select a Cotton Cloth - first put the cloth as cover and then put the Usual Polythin Cover for water Proof
Not ur bike is proofed for Scratches and also for Water...(my way)

see washing too frequently will cause rust formation and fading of paint, i generally wash my bikes only once a month, not more frequent than that. And that time they get a coat of polish and look spunky fresh from the showroom.

Otherwise, its a normal bike cover from reliance automart, that keeps them covered most of the day, and a wet cloth and a dry cloth to wipe em clean.