Is it possible to mount cartridge without using a protractor?

Hello-

I recently purchased the Technics SL 1200 GR TT and have mounted the MoFi Master Tracker cartridge. My friend actually did the set up for me, including adjusting the arm and the phono pre. It sounds pretty good! We did this without using a protractor as I didn't see one shipped with the TT and he didn't bring one (was thinking he would)

Question is-

Should I continue to play music and order a protractor for an "official setup" or wait till the protractor arrives and adjust accordingly. I don't want to mess up the stylus or my vinyl if it's way off. I can't imagine it is as it sounds pretty darn good. 

Thanks!

Ps: Ordering the Mint Best Tractor