To estimate a maximum purchase price for the coin in question, we can consider several factors:

1. Coin Condition: The coin to be auctioned has a condition rating of 95 (EBC+), indicating that it is in very good shape. This generally translates to a higher price compared to coins with lower conditions.

2. Starting Price: The starting price is 600 euros. This is a good starting point, but not necessarily the final price.

3. Auction History:
- The average hammer price for similar coins in the past is 267.6 euros, but this can vary depending on the condition.
- In previous auctions, coins with similar conditions (90-95) have reached hammer prices that vary significantly, with some reaching up to 1900 euros (as seen in the 2014 auction).

4. Price Trends: By observing the hammer prices of coins with conditions of 90 and 95, we can see that there is a wide range. For example, in recent auctions, coins with a condition of 95 have reached hammer prices of 800 euros and more.

5. Market Expectations: Given that there is a scheduled auction and the coin is in good condition, it is reasonable to expect that bidders will be willing to pay a price above the starting price.

Based on these factors, an estimated maximum purchase price could be between 800 and 1200 euros, considering that the condition is high and there is potential interest in the coin. However, the final price will depend on the competition in the auction and the interest of collectors.