, I just use one brush for brown and one for black although I hardly use them for polishing. In my experience polish generally won't greatly effect colour of you shoes though it does vary per type of polish used. The (saphir) stuff you find in the little glass jars that has a creamy consistency contains a substantially more pigment than the 'wax' from the tins. Kiwi from tins on the other hand contains more pigment than saphir or LCA. (Are they the same btw?)
Personally I'm not a big fan of neutral polish as in my experience it has a tendency make shoes look a little dull. I'd use light brown or even mid-brown for your lighter non-black shoes and dark brown for your darker ones. Should be fine. If/when you think the cherry pair is loosing too much red, switch to burgundy.
As an example, here is a pair of CJs I coloured using only burgundy kiwi polish from a tin and even then it took ages to get the colour going. I repeatedly polished the same spots dozens of times; notice the 'line' next to the eyelets for instance.
Don't stress out too much about using the right colour polish, you won't ruin your shoes that easily.Warning: CJs (Click to show)
, I don't follow this thread well enough to know every member's reputation as this isn't my native forum. Sadly the internet and the anonymity it offers often brings out the worst in people though I've haven't seen that side of Stirling