Seeking advice on bike Sizing

I'm 6'1" with a 36 inseam and I am thinking of taking an 19.5" L size hybrid bike because that's a vastly available frame size for my height. I've done huge research and checked various forums and online size calculator sites and according to the charts they provide, they all seem to follow a standard relation between overall height and inseam length. And I understood that my body proportions are off those standards. According to that standard if taken the overall height, the 19.5 inch frame should fit me. But when I take the inseam, things get strange. According to the inseam length suggested size I need to go for a 21" frame at least, because my inseam length falls in range of a 6'3 or 6;4" person. Now this is really confusing and it would really help if someone clears me of this. Unfortunately I'm far away from any major city to test the bike physically in a shop and I'm buying online. So please help me if i should go for a 21" XL size, if so will it be too big? Or I can fit the 19.5" frame with some major adjustments which seem unavoidable considering my abnormally long inseam for my height? Thanks in advance.