fast moving momentum trade, market or limit order?

good morning.

have started paper trading with the TC2000 software.

1. with regard to entering trades (momentum type intraday trades, stocks) i see i can
get filled fairly fast by entering as a "market" buy, but i see from slippage many times
i am overpaying a bit. A limited add doesn't get me filled very fast, and by the time i
do get filled it could possibly be too late.

what is the best technique to prevent this? for example a "limited" buy with a "0"---
would this get me filled almost as fast at my specific price point?

2. let's say i enter a trade and it gives a good upward spike. So i want to add shares. Let's
say i entered the trade, it is making $, i have a tight stop on it which i can manually adjust
with this software, so if i add another 500 (or 5000 shares), can the initial stop i have in
place control all adds, or do i need to create a new stop for each add?

(i'm hopeful that i can control and save any gains with only my initial stop i placed with
my 100 share buy)

thanks for any insight.

fast moving momentum trade, market or limit order?