Pilot Hi-Tec-C Cavalier Gel Ink Pen Refill - 0.4 mm - Blue

I've tried the 0.4 and 0.5 Hi-Tec-C in the disposable version. I found the 0.4 to be a bit on the scratchy side but the 0.5 is still fine enough without the scratchiness.
I want to upgrade to Cavalier but it seems that a 0.5 blue refill is not available. Would anyone else be interested in a 0.5 refill for the Cavalier?
Just putting it out there in the hope that demand may induce supply.

I agree with the 0.5 request. So until they make a 0.5 I am googling pen hacks for this pen. but i am loving this pen.

I have been using this been for about two years and have all good things to say about it. It's thin in the hand but still carries enough balance to make for a smooth writing experience, although I wouldn't recommend it for extensive writing, e.g. a letter or journal entry. I use it mainly for my checkbook register and my Moleskine planner. The ink flow is smooth on the blue .4 refill but on the dark side, which is how I like it. Just be careful on the paper you use - it tends to bleed on lower-quality, thinner paper. Since the ink flow is so smooth, little pressure is needed to actually get the ink on the paper.

Love the pen! Would also like a .5 black and/or blue refill.

The ink dries very fast because it´s a super thin point. Only recommended for very small text