Of course this approach does require that you keep a potential delay (if you do miss the connection) in mind when planning the rest of your schedule at the destination country. Also depending on the flight loads those flights 3,5 or 7 hours later may be fully booked causing a larger delay. You may be able to estimate that based on flight loads for today's flight and current availability for the flight(s) on the day of travel. Though there's always a small chance that if you do miss the connection that you will be stuck in Amsterdam for a little longer than you'd like. Which, depending on the kind of trip, may be an issue..or not.

So my (seemingly controversial opinion) would be to book the 3,5hr connection to allow for a little delay and make sure there won't be any stress and/or running around the airport. Or book an even longer connection if you'd like to see Amsterdam. If you do head into the city keep in mind that the train ride is about 20 minutes, and may take up to 30 in case you need to grab a taxi - and without priority I'd aim to be back at Schiphol 2 hrs before departure of the intra-Schengen flight.