Scaling in is definitely the way to go in my opinion, even 100 point intra day trends can become 5:1+ reward to risk trades whilst still giving your stops wiggle room
Usd/jpy is currently trading around 110.15, if you think you have a pretty good idea of the next 100 point move instead of hesitating over the perfect entry get in at market at what you feel is a conservative risk amount, place your stop just beyond support or resistance, for Instance if going short place it a little beyond the previous high of 110.47, so say at 110.55 (40pips) .
Now you might use the break below 110 as your confirmation and double your position and move your stops to maintain your initial risk or breakeven, on the way down to your take profit you may see a 30 or so pip pullback or 2 and take this opportunity to add to your position again at a good price once it resumes downwards, now you've hit your take profit at 109.30.
you entered at £4 at 110.15, upped it to £8 at 109.95, again to £12 when the market pulled back 30 points back up to 75. You made £780 profit and your initial risk was only £160.
If you would have waited for the break of 110 and got in at £5 a Point at 109.95 and took profit at 109.30 you would have only made £325 and your stop if you used the same previous high method would be £300, huge difference in Reward to Reward by adding at key levels.
Ideally i would shoot for 200+ pip moves as they can really hit big but you have to be prepared to be wrong a few times, used that as an example as i have the order in already on that one, fingers crossed