$MAGMA |Daily chart above MA200|MA200 0.2999
Before looking at position size, first understand moving averages.
On the daily chart, MA200 is the average closing price over the past 200 days, often used as a reference for the bull or bear trend; MA50 is often used to gauge the medium-term trend.
Many people wait for the price to move above a moving average and then pull back without breaking below it before taking the move seriously; after a break below, they wait for a rebound that fails to move back above it.
Working out your order size based on where you place your stop-loss is much more reliable than choosing a position size by guesswork.