Go for it my friend, since we spend 90% of our life talking and practicing in our m1 it is natural for the m2 to sound "crappy" at the beginning, I swear I sound like shit in my high m2 most of the times but it also sounds loud and like something I would love to dive in, PLUS you notice  how it starts benefiting your m1 right away. There are lots of good beatles songs to put m2 into practice, "helter, oh darling, I saw her standing there" 

totally relatable.  Paul in particular is so good...it's tricky to sit in his range...but consider this...their voice were "worked out" in clubs early on doing sometimes 8-10 hour gigs...they'd play I think 5 or 6 sets a night.  So imagine they had to find an approach that allowed them to sing for that long and not literally grind their voices into dust.  I am sure early on that was easier said than done...but imagine some of the M1 coaches or mixed voice teachers doing 5-8 hours of live singing several nights a week.  Sterling Jackson is the real deal and he does have that stuff worked out and is a legit gigging live singer....hope that helps a bit.

Hi mate.

I was in a Beatles Tribute band that pretty much put the the nail in my singing coffin.

People underestimate how difficult Beatles songs are. I played both John and Paul and found Paul easiest as I could use M2. The John parts as you say are all around G3 to G4 range which is for me certainly my weakest point. I am unable to sing with enough power in my and my chest voice just flips at the C4. I almost feel like I used "mixed voice to well for years that I am now unable to pull chest at all.

you can still use M2 to hit notes with ease but trust me once you start with M2 you'll wanna try to sing higher and higher. that's how it was for me!

I think I understand. I remember believing I'd be 100% 

satisfied with mastering a G4 or an A4 consistently. Having been stuck at an F4 for so long, I really idealized those two or three additional semitones. Having to accept they weren't going to happen without changing my entire technique was discouraging for sure. But worth it in the end.