Some define 50/50 conditions differently. For me, it means that when you're riding the 50% dirt part ... well, anything can happen, especially in unfamiliar territory.

The OP uses the term "Exploring". To me this indicates he may end up on dirt tracks that can start out fine ... but after few km. can get nasty, muddy, rocky, and steep.... no way to make it on a Vstrom and maybe TOUGH on the GS, Tiger or even the AT.

You just can't always predict the condition of every remote back trail or even Forest Service Fire road ... so do research best you can and take your chances ... but if really exploring, a more dirt oriented bike would be my choice. YMMV.

Anytime the trail gets even slightly technical, a 21" front tire is a welcome addition over a 19" or 17" front. And frankly, even on tarmac the 21" is not bad with correct tires for pace and conditions. There really is no "down side" to a 21".

So, if your 50/50 means that the dirt part of the 50/50 may get technical and you don't want to have to constantly turn around at the first tough section ... then a more off road friendly bike could be the better choice.

This is why I finally sold my Vstrom ... bought a Suzuki DR650. But even on my DR650 (40 kg. lighter than Vstrom), I've run into plenty or situations where things got too tough for me ... I end up turning around.

I'm now looking at a 250cc bike ... WR250R. This is obviously weighted in the dirt part of the 50/50 equation ... but it's really quite good on the road too.
I will keep my DR650, a great all round bike that costs little to run.