I think it doesn't matter as long as you stick with it.
The reader notices.
I had a favourite artist of mine swtich between coloured pages and black and white pages several times and it is really really annoying. The reader doesn't care if you feel insecure or think your style is not good enough - for them to be following your work, they must like it. The reader wants consitency.
However, I think people on Tapastic are generally pretty accepting, because most readers are artists themselves. If you decide you like black and white pages, it's cool too, but be sure you want to make the switch so you don't have to keep changing styles - some people would stick with you, some, who are not as invested, might not.
But if it's only the time that worries you, remember, it's always quality over quantity.