Blackjack Cost of underbetting... and other questions.

There seem to be newbies and recreational counters here and hearing from the pros might help. As losing mounts, maybe a losing streak, I find myself betting even more conservatively than normal. Then, when I review a session, I wonder if I lost because I was underbetting, I dont really know the answer for sure. There are a couple of other questions as well..

For example, in a DD game, after the first round and only maybe 8 cards have been played, the running count is +3, normally, I raise my bet from the $25 minimum to $50 but when I have lost a bit of money, I stay with the $25 bet because its early in the shoe (even if the true count would be higher than 1.5). I sometimes reduce my max bet from $150 to just $100. I wonder if delaying my ramp or lowering my max bet is hurting me.

On A,7 versus 9-A, the strategy is to hit but when should one deviate from it? Should we stand when its high negative or positive? (One deviation among many I dont know).

Another one I dont know off the top is 4,4 vs 5,6. When to split, double or hit.

Answers appreciated. Please dont make it up about me.

Source.