The tallest peak is called the base peak and its the most STABLE fragment.
Yes, the molecular ion peak is always the one furtherest to the right. This represents the UN-FRAGMENTED molecule minus one electron.
However, be careful as there could be isotopes present and this could give you an M+1 peak. However, you will know if this is the Molecular ion peak or not as the the molecular ion peak should be greater than the M+1 peak (isotope peak)
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