Well it wasn't until I read 63BKPKER post that I was surprised no one else posted as I was going to post the same thing. I agree MEETING the land owner in person can do more wonders than a land owner reading an e-mail or letter.
Think of a salesman aspect of it. If a salesman sent you a letter or an e-mail to "TRY" and sell you something, how would you react?
Many here will just "IGNORE" the letter or e-mail; BUT,
How many of you here was not in the mood to buy anything, but went somewhere, like a motorcycle rally, car show, or just out tire kicking at a car dealership just to see what was there but had "NO INTENTIONS" of buying anything? BUT; Some of you bought something anyway even though you had no plans on spending any money at that moment.
I always wanted to find and search for lost cache and treasures, and still doing some research when I get a chance.
I used to sell motorcycle products at motorcycle rallies, I have sold products to people who were informative of "NOT SPENDING ANY MONEY", OR COULDN'T AFFORD to spend it or HAD NO MONEY! I didn't "hound" them. I explained about my products and "LOOKED THEM DEAD STRAIGHT IN THE EYE" with a smile on my face and (words of advice, TONE OF YOUR VOICE NAD BODY LANGUAGE HAS EVERYTHING TO DO WITH COMMUNICATION to someone face to face), smile while communicating.
I would stand in my booth and someone would be walking by, and I would tell them to come here and see what I have and many would just shake their heads no or reply with a no or not interested, but I would not move out of my space and would insist they come look. 98% of them came to me.
Face to face is way better presentaion and each person can get a better feel for each other. Fact is yes, you may have to travel to do so! So you need to see if it is worth you spending the time and fuel to go meet with him. The best time to meet him would certainly not be in the evening he may have had a bad day for some reason. Offer to meet him for lunch and pay the tab.
Over lunch can have a good communication with everyone, and you can explain just enough of what was done for the research, but don't sound desperate.
Personally I don't think you should have mentioned any dollar amount to him. You should have left it, "Well, I been searching for lost caches and old relics from such and such eara, and I came across one on or near your property, but I do not know the exact amount in dollars or what it is worth, it may not be there anymore, or the amount may only be a few dollars" "If by some chance that it is more than a few dollars, or the relic is valued at a high price, myself and my partner will split everything with you 1/3 for each of us."
If he asks you why do you search for things if it may not be worth much or don't find anything at all? Then you would tell him that you have found some things before that were worth a lot of money, sometimes I found things that are not worth much and sometimes found nothing at all, and also found some small cached coins before and it is a rarity that you find a lot of valued things everytime, but sometimes one gets lucky, but it is RARE, but you do it for the thrill of the research and to see if the find is real."
Don't sound desperate to him. If he still insists on a 50/50, then thank him for his time, kindly let him know that without your research and info, he will never even find it, know about it, and you have other caches, relics you are searching for that are more promissing, then kindly stand up, shake his hand, and walk out. (Word of advice, If he insists on 50/50 as I mentioned above), give him the presence of you "Really don't care what he wants and give the impression you could care less about his property or the cache/relics! You don't have to speak, BODY LANGUAGE says a lot!
He will MOST LIKELY take you up on your offer being you all had time to sit over at lunch and talk about and had time to think about it and if you start to walk out and leave he may go ahead and change his mind.