You have one misconception.
Is it better to sit at 1st base in order to make the most accurate wager decisions or 3rd base in order to make the most accurate playing decisions?
The first part about 1st base allowing a better wager decision is your misconception. I'll get to that in a minute.
You and gorilla player are correct about 3rd base allowing for a better strategy decision since you have more intelligence (albeit tiny) about the remaining cards when you play your hand.
It seems to me that if the count is high and I up my wager sitting at 3rd base on a full table the count could drop dramatically before my cards are delt.
Voodoo. You are thinking about a flow of cards. Look at it this way. Let's say it's a full table with six seats. A hand is dealt consisting of 14 cards (two cards for each player including the dealer's up and hole cards) The count drops 6 points because 4 little cards and 10 tens were dealt. (I'm using a single level count here, of course.) This is simply a mix of cards. Those extra tens could have landed at your side of the table, the other side or influenced the dealer's hand.
So, there is no edge to be gained from seat position for betting decision, but there is a tiny edge to be gained from sitting at third for strategy decisions.
Personally, I like to sit next to third base. My titanium neck has limited movement, and moving my body to count the whole table could draw attention. I find from that seat that I can view well, I'm late in the deal for strategy decisions, and I minimize the peeing and moaning about 3rd taking the bust card.