I would only be concerned if my fingers were stretched more that normal while doing the "Shift+G" using left hand. But your current speed suggests you have already gotten habitual to it.

By the way, how do you do Shift+A using your current method?

Pinky on the shift and ring finger on A. Same with Q and Z.

Okay, so do you ever use right shift key?

Tried it a few times, that's it.

I had that, too. I used the left shift almost exclusively and had to make a conscious effort to change that. The only time I don't use the right shift for left-hand capitals now is for 'T' and for sentences that end in '!' and are followed by a sentence that starts with a righthand letter.

I do the 'T' because it is almost always followed by a 'H'. Since my righthand pinky is usually resting on the 'P', I'd have to bend my wrist very awkwardly to reach the righthand shift and be able to hit the 'H' directly afterwards, instead of moving the whole hand which is what I usually do when I need the righthand shift.

I feel that switching to using both shift keys has made my typing not neccesarily faster, but more ergonomic and more accurate. That's just one opinon, though, so do what feels best for you. It's not like there's any real benefit to improve your typing beyond the level you're at now, except vain ambition.

When typing letters that must be capitalized, it's best to hit the Caps lock key, hit a letter key then hit the Caps lock key again. When you must type a symbol or a punctuation mark key, you should use the left shift key, especially if you're taking a typing test because accidentally hitting "Enter" while trying to hit the right shift key might result in a fatal error that kicks you out of your test.

I have heard it said before that caps lock is best practice, but I can't rationalize it only because it requires three key presses to do the same thing you could do in two key presses. When the goal is to increase speed; each key press is a valuable amount of time and effort and I just don't see it being efficient unless of course your are typing entire words in caps.

That last sentence is so very sad, but true. :(

It's easier and quicker to hit the caps lock key and if you choose to use a Shift key, you have to spend more time holding it down while going for a letter key to hit. Using the caps lock key lately has made me faster.