How to determine offer amount.

We are interested in a house that listed at 500k they have since dropped the price to 475k and have spent 122 days on market. The house needs some updates and work. We want to offer around 435k. That’s about 91.5% of the listing price. Do you think this is a lowball offer? We don’t want to insult them but we need money to do the updates in the house.