How long a timeframe you look at depends on yourself. You must know the reasons why traders choose different timeframes:
People trade over longer time frames to catch bigger movements. I’m not really interested in trades that don’t look to move at least 100 pips. Because of the longer time in a trade, more up and downs are to be expected. I have many times been up 50 pips, watched it go down to 0 pips, then watched it go down to minus 50 pips, back up to 0 pips, then all the way up to plus 100 pips.
Because of the drawdowns, a bigger stop-loss distance is needed. Therefore a smaller position size is needed too. This depends more on your psychology. Can you handle being 10% up only to then watch this go into drawdown of 10% so you can wait to be 20% up or more?
If you find this is easy for you, you are a special type of patient person and you could increase your timeframe and only trade off the weekly chart in the direction of the trend on the month chart.
If this much movement is too much for you then you could train yourself to be able to handle it by being consistent and sticking to your decisions. This is what I am doing starting with only 1% risk per trade and gradually increasing it as I grow some balls.
If you’re not interested in doing this, you could shorten your timeframe and increase position size. But the whole philosophy of this strategy, as I understand it, is that the shorter your timeframe gets, the more similar to gambling, the more addictive and obsessive trading becomes. Not to mention that the shorter your timeframe, the more time you spend staring at screens stressing yourself out.
So my answer would be:
Go as longterm as you can handle and try to increase your ability to handle big movements.
Big movements is what we want here but the market moves in two directions.