well, you made it pretty clear that its right to left, which is a big butt-saver. and it does look pretty authentic, so im personally not thrown by the right to left-ness.
however, i dont know how much the rtl setup works outside of japanese-language comics regardless. i understand the authenticity motivation, but as others have mentioned it causes a clash with the text direction. also, youre making your comic for a western audience (youre posting on a western site, for mostly westerners, in english) - its easier to accept that, and that your webcomic is manga style as you stated, and not manga, than it is to alienate some of your audience and potentially cause yourself lettering problems.