Your friend is suggesting mechanicals because it will save you the trouble of having to properly tune your bow.

Personally, I would find a good cut on contact head like a Magnus Stinger or a Montec and work with your equipment until you get your field points and broadheads hitting the same.

Too many things can go wrong with mechanicals for me to trust them. Considering you're using an older bow, I would wonder if you'll have the needed kinetic energy required for mechanicals anyhow.