Sounds like you are going through the same struggles I went through - praticality vs what your heart wants.
I, too, lusted over the Small (in canvas/brown) for months and even missed the chance (twice!) to buy it at the price before the price increase that happened in Nov 2020 (CAD$2850 -> CAD $3055)
and finally pulled the trigger but on the Mini. Tried it on at home with several outfits and even asked a bunch of people which one they think is a better choice (majority chose the Mini) but for some reason I still couldn't get the Small out of my head and it felt like I was cheating on the Mini
. I almost convinced myself the Mini is a better, more practical choice but at the end I went back and exchanged it to the Small and so far I can tell you it really makes my heart sing every time I look at it.
The shoulder strap doesn't seem to be a problem for me (even when the bag is empty) and I like my corssbody high so, again, not a problem. With the Mini, I even considered getting more holes punched on the leather strap so I can wear it higher but my SA told me that would void the 2 year
Gucci warranty so that's no bueno :/
For me, ultimately, I threw all pros and cons out the window and went with what my heart wants - like when Miranda had that giant list of pros and cons (more cons than pros) on Steve but knew what she wanted when she saw herself with the milk-stache and Steve on the Brooklyn Bridge. SATC fan anyone? hehe. It's not like one of them is completely useless and from personal experience if I really love something I've always found a way to make it work especially when none of the "cons" on the Small are a deal breaker. Also, when I look at the Small I feel like I got more bang for my buck even though the Mini does come with 2 straps but somehow Small just feels more luxurious to me.
All and all I'm definitely not dissing the Mini here but from what you've mentioned I think you should go with the one that gives you butterflies
PS- in Canada the Return Policy for in-store purchase is 14 days for return and exchange and 30 days for online purchases so interesting to hear there's no refund where you are
PPS- maybe post some mod shots? would love to see the Small on you!