I'm sorry but I've played Bo non-stop since he was released and I can tell you he ain't doing shit in that matchup. Grandmaster can take his sweet time, walk back and clone, throw iceballs whatever or go in with his strings into safe burst on block. He literally has no risk involved when playing against Bo, he can do whatever he wants and wait for his chance to get damage.
Now that ice burst is -5 he can just do anything into it and be safe, again no risk at all. His one unsafe option, b2 can't even be punished by Bo's standing normals! The best he could hope for is a bf4 which pushes Sub full screen where he has the advantage. Sub has a WAY better neutral than Bo who has no neutral at all really apart from his d4 (non-bartitsu). If Bo gets a touch and puts Sub in the corner then sure he can win, but that's just every matchup for Bo in a nutshell for the majority of the cast. Difference here is that Grandmaster has an equally scary corner game going and way better mid/full screen game.
Bo is not winning this matchup dude. It's not unwinnable, probably like 6-4 in favour of Grandmaster, but there's zero chance Bo is a "hard" matchup for Grandmaster.
edit: on the subject of good combos the majority of the time with Bo you're only going to be hitting 18-22% mid screen because you'll go for his mix options of course like 2~flips, 24~flips, 244~flips, b233~up flame, b2~flips etc or f3, b3, b1 etc in up flame, rc 2~flips for about 22~24% AT MOST, only way you're breaking 30% is if you commit 100% to one of his totally unsafe launching string likes, 21, 341 or 413u4. Apart from that your options are to hitconfirm into meterburn up flame or meterburn fart. In the corner Grandmaster can get 40+ percent off every touch with the clone, this character has INSANE damage, Bo does high 30's meterlessly so it's comparable but he needs to spend a bar to get anywhere near what Grandmaster does meterelssly with just the clone.
Also the clone is way better than fart/meterburn fart and because of the way Sub can and should play this matchup it doesn't matter unless once again Bo has him in the corner.
Don't get me wrong I think a lot of Bo's matchups are 5-5, 6-4 in the opponent's favour with very few 7-3 in the opponent's favour or harder matchups but this is not one he wins.
edit 2: Yes bartitsu does have an easier time dealing with the clone but it's still not in his favour, probably 5-5 bartisu vs grandmaster.
