Some answers
"Illustrious 18 states:
"Split 10s vs 5 at TC 5
"Split 10s vs 6 at TC 4"
I'll take your word for it! :-)
"My 1st question is, you receive an ace on your first split; do you double down or stand?"
You stand, if you want to be able to walk later on! :-) Seriously, you didn't state what the count was. There are (Hi-Lo) indices for soft doubling A,T vs. 5 and 6 (they're both about +8), but I can't think of anything that could potentially get you thrown out more quickly.
"2nd question, do you continue to split if you receive 10 cards as long as the TC dictates to?"
Same type of answer (first part) as above. Technically, in for a penny, in for a pound. If you're the type who does it if it's "right," then you do it. Personally, I stopped splitting tens ages ago.
"I haven't gotten the nerve to do this split and would only do it heads up... I feel like I get enough heat as is and this would only add to it..."
Then, get ready for the time when you have your max bet of, say, 16 units out, you get T,T vs. dealer's 5, and the count is so high that you split away three 20s to make four hands, make various totals from 12 to 20 on all of them, dealer has ten in the hole (of course), and hits it with a ... six (also, of course!). And, whatever your unit is, you sit there and realize that the swing is 128 units, had the dealer busted. (And, in the old days, splits used to be unlimited and not restricted to four hands. Think about that "fun.")
"I also can't stand doubling 10 vs dealer's Ace or 10 at TC of 4 but have done this... It just stresses me out when I do... lol"
You might use the risk-averse index of +7 for doubling T vs. T, to ease your stress. Or, you might choose not to do it at all. I'll forgive you. :-)
Don