For Form 2210 Schedule AI, TurboTax is asking for "Self-Employment Income-TP". Should I enter our total gross self-employment income in that space?

This question is asking for the Self Employment Income of the Taxpayer.  That would be the Net Self-Employment income amount from Schedule C.

Form 2210 is trying to calculate whether you owe a penalty for not withholding enough (or paying estimated taxes) on your income in 2018. 

There are exceptions to the Penalty, and TurboTax will guide you through this section. 

Here's more info:

https://ttlc.intuit.com/replies/3300251

Thank you! That helps a lot.

To refine that a little, it wants the sum of the "Net Profit or (Loss)" lines of the one or more Schedule C's of the taxpayer (as opposed to any spouse).