I use the .98 for breaking as it covers the non-leather tips without that hard application. Have used one cube going on third year, and less than half gone.
0.98 is really nice, I understand some peoples issues with it, but I lightly feather a corner over the cue, and it works fine. Cueball does need a clean every rack (Imagine you know that if you're breaking with it). Exceed chalk is pretty nice too. It's somewhere between 0.98 and a piece of regular chalk.
I would say the only time I notice chalk making all that much of a difference (as someone who chalks every shot), is when breaking. Especially MR format from the box. Could just be my finicky little brain however, but I do need to adjust slightly, and I assume that is grip related (Will hold my hands up and say that is just how I feel about it and no real science in it on my end

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Use Pag's blue and green (cloth color determines which).
I have a piece of the blue, and it's quite nice
Sounds like the TP7500 would do for both, if color didn't matter.
Yup, most chalk will do the trick. As someone who has been given lots of chalks and feedsback to a few different brands, colour, feel on application and how it applies to the tip, are subjective factors which affect our perception of 'good' - but all we really need is clean coverage. I would be happy with TP, DJH/pagulayan, 9half, Exceed, HR Max... Probably stick with this block of Exceed for a while, as I like the colour, and combination of cleanliness and slight gritty feedback on application.