Towing, TC lockup and Ping

[FGCUhank]

I'm looking more for theory from the experts rather than problem solving. It has been a while since I've been on the board so I'll post the short version of my story.

I have a AWD Chevy Astro V6 with 2" lift and 28" AT's. The speedo/tire settings have been updated and are accurate. The kick is that I pull a 25' travel trailer that is on the high side of the weight limit of the van. Basically I bought the wrong tow vehicle but I am stuck with it for now.

My first question is about TC lockup. When towing, to reduce heat, should I set the TC to lockup as soon as possible? The factory settings for tow mode were a bit slushy so I have trimmed it down a bit. But for example the 1-2 shift was at 19 mph but lockup was not until 32. I have trimmed it down a bit but was thinking of going more.

Second question is about tuning for ping. With the TC locking up more/longer I notice more ping due to the load. Should I address the ping by building up a histogram table, pull the ping from the spark table, smooth the table then repeat till all the ping is gone?

Third question is borderline desperation. Any of you guys have experience with the Astro van and have any ideas how to reduce IAT's? The IAT's, most likely as I am in SW FL, frequently creep up to where the ECM starts pulling timing. If I am on a trip and we stop for gas/lunch the engine heat buildup gets so bad that I am pulling timing right off the bad. Anyone have clues or ideas on how to get heat out of an engine compartment of a van?

Note, on question three I do have a huge transmission cooler, trans temps are always below 190, and have opened up both sides of the factory air box. It just seems all that hot air gets trapped under the hood more so than a car or truck with more space to blow around.

Thanks for any comments and tips.

[FGCUhank]

One last comment/question. How much lag time should exist between a shift and TC lockup? Ideally I think I'd like the TC to apply and lock in 2nd and then hold during the rest of the shifts. The log above looks like that is not happening. It is a very short log and I put in markers at each shift and when I felt the TC lock.