Well, I did not know where to put it - nibs&tines, pen reviews or else
So this seems a good forum.
I pursue flex almost from the beginning of my fountain pen journey. I was fortunate enough not starting with modern flexes, but with a vintage one. I fancied a vintage pen, and bought one just because it was cheap, looked nice and I knew the brand. Parker Slimfold - in terms of size it was a disappointment (i didn check its size or asked the seller), - but the nib was fantastic. Right away i fell in love with "flex". Bought another vintage (Wyvern) - also great. Then started looking at moder ones - Conklin Omniflex, Ahab etc but nothing compared.
Alter some time I learnt more, bought and used much more pens. Realised that flex is quite a wide idea. soft, semi, regular, wet noodle, modern, vintage. Waterman 52 flex vs vintage MB 146 flex vs flexible Pelikan nibs in 140, 400 etc. Soft nibs in M1000 vs japanise SF nibs.
Pilot Custom 743 with FA nib is another part of this journey. I got to know and like Japanese nibs only recently. I knew about Pilot Falcon but did not like it, then "discovered" 912, 823, 742, 743 etc. And definitely wanted one with FA nib.
So I ordered one. Pilot Custom 743 to be exact. In Europe they are not sold at all, so for the first time I took a risk and ordered from Japan. The price was incredible, good seller, but he sent it with the economy not expedited as I ordered, but any way 10 days later it was home I did not pay any duty or taxes (typically for import from Japan its est 28% total, but not this time - customs missed it?) .
Pen is very nice, very well built but nothing especially interesting - just another cigar shaped, black rather large pen with gold trim. And 14k gold nib, in an unusual shape - with cutouts.
It is not a vintage full flex but is much better in this area than any of modern so-called flex nibs I had a chance to try. I'm not a calligrapher, I'm still working on my handwriting. But I can appreciate a good nib.
With a light touch, it puts a thin line, Japanese fine, and is smooth. but even slightly pressed it goes medium, broad and double broad quite easily, but at the same time, it becomes scratchy. I'm not sure it should work like that.
The only problem I had was railroading then I flexed it too much or for too long, or was writing too fast. I investigated and wound aftermarket feed at flexiblenibs.com - 4 versions to be exact for my pen !!! Actually also for 823 and probably 845 pens too. Japanese ebonite, CNC cut, two colors (black and red) and two versions (2 slits, and 3 slits one for wet inks or not to aggressive flexing, the second one for dry inks and heavy pressing. I ordered both versions in black and several days later herre they are. Fixed the problem like a dream.
The feeds are PERFECT. They are super high quality, shapes matches the original with 0,2mm precision. I really recomend one for any FA nib user on 743/823 (#15 nib) pen.
Pictures and writing samples below.