Nasty Lead

Playing in our local Sectional this weekend, you are playing in the first half of a KO match. With everyone Vul, you pick up 5 AKQ9743 AQT2 6 and hear partner open 1C in first seat. You bid 1H, partner bids 1S, and then bids 3C over your 2D 4SF. You bid 3H and partner now bids 3N. Hearing about a probable Diamond card encourages you to jump to 6H, ending the auction. For ease of viewing, here is the auction again.


N   E   S   W
1C P  1H  P
1S P  2D  P
3C P  3H  P
3N P  6H  P
P   P

LHO thinks for a minute and then leads the 8 of Spades and this dummy appears

AQ73
T6
53
KQJT4

5
AKQ9743
AQT2
6

What do you play at trick 1, and how do you plan for the play. And besides the fact that partner should have bid 4H over 3H, not 3N, any other problems with the bidding. Finally, does it make any difference as to the style of the person on lead, whether they listen to an auction before leading, or just lead 4th best all the time? And of course, the leader found the only lead available to present a problem on the hand, don’t they always.
 
Think about the hand and I will post the whole hand in a day.