Before choosing the deadline, do you know anything about the seller’s motivation? Sixty-one days may matter if they need a particular completion date, but it could mean very little if they are prepared to wait. Also ask whoever is assisting you to separate completed comparables from current...
Don’t overlook the fallback plan. If the named contact is unavailable near an offer deadline, is there a shared file and another person able to respond, or does everything wait? Likewise, can you take the valuation report elsewhere if you decide not to use the negotiation service? Portability...