how to make an offer to a property that doesn't need any repairs?

[Cesar Garcia]

I have a seller that wants to get rid go his house, the house ARV is about 500k

he has been improving his house since he bought it, the house is in great condition and it doesn't need any repairs, maybe just re paint two rooms but that's it, everything else is updated, i would generally use 70-80% - repairs - wholesale fee = offer price. 70 - 80% depending on the area and the market, but this seller doesn't want to go to a realtor and just wants to sell his house by himself, i made him an offer of 350k but he said if I could do better, the thing is im pretty sure if he puts it on the market he could sell for 500k as is,what would you guys offer in this situation? thank you!