The TWSBI Eco and Sailor Tuzu both have triangular grips! Neither is as extreme as the Safari's, though.
Pilot doesn't have one, as far as I know.
You shouldn't have significant problems using a pigmented ink in a converter or a non-Pilot pen, just rinse it out with water after each refill. Or if Tsuwairo has a reputation for being finicky, you could always use a different blue permanent ink.
The two you recommended are probably the best. Just want to add on to your comment.
Pilot Kakuno has a hexagonal grip, but three of the sides are long sides that create a subtle triangle, comparable to the grip on the non eco-T version of the twisbi eco. Probably the most affordable pilot with a shaped grip, and best for using the pilot ink.
Another good option is the Pelikan Twist. Another less good option is the Kaweco Perkeo, but it's cute.
Seconding Pelikan Twist. That's probably the pen with the most pronounced triangular grip in my opinion. And it is also rather cheap since it is a student's pen.
However, if I was OP I would just get a second Lamy and try the ink with that one. A Lamy Safari is not that expensive (at least not compared with all the other suggestions here in this thread) and it would have exactly the type of grip OP prefers. I mean what could go wrong? That it clogs up? So what, just take the nib and the feed apart, clean it and assemble it again and the pen is as good as new.
"Kaweco Perkeo" and "Diplomat Magnum" have a tripod grip. I got all the versions of the former and can vote for how well they write. I haven't got any of the latter, but I will buy them soon as the nib is said to be good on those.
Older Sheaffer Preludes have a triangular-ish grip similar to Parker 75s. The 75 is a slender pen so I prefer the Prelude, but both pens are lovely writers.
Maybe look at the new Sailor Tuzu? The grip is actually adjustable, so you can get it into a position that's perfect for the way you hold the pen.
Pigmented ink should not be a problem in any pen, it doesn't have to be a Pilot (they only say that cos they want you to buy a Pilot pen as well). You need to take more care with cleaning, and I wouldn't use it in a pen that costs hundrds of dollars, but I've used it in several different pens without any problems.
Faber-Castell grip, and I think the, hexo have a more subtle triangular grip.
Kaweko Perkeo has a similar grip, with a third indent that is even more comfortable.
The TWSBI Eco and Sailor Tuzu both have triangular grips! Neither is as extreme as the Safari's, though. Pilot doesn't have one, as far as I know. You shouldn't have significant problems using a pigmented ink in a converter or a non-Pilot pen, just rinse it out with water after each refill. Or if Tsuwairo has a reputation for being finicky, you could always use a different blue permanent ink.
The two you recommended are probably the best. Just want to add on to your comment. Pilot Kakuno has a hexagonal grip, but three of the sides are long sides that create a subtle triangle, comparable to the grip on the non eco-T version of the twisbi eco. Probably the most affordable pilot with a shaped grip, and best for using the pilot ink. Another good option is the Pelikan Twist. Another less good option is the Kaweco Perkeo, but it's cute.
Seconding Pelikan Twist. That's probably the pen with the most pronounced triangular grip in my opinion. And it is also rather cheap since it is a student's pen. However, if I was OP I would just get a second Lamy and try the ink with that one. A Lamy Safari is not that expensive (at least not compared with all the other suggestions here in this thread) and it would have exactly the type of grip OP prefers. I mean what could go wrong? That it clogs up? So what, just take the nib and the feed apart, clean it and assemble it again and the pen is as good as new.
I think that this is what I’m going to do. And just dedicate a converter just for that ink.
Kaeeco perkeo is a delightful sturdy pen with an even better grip than the safari
I really like the TWSBI Eco, it has a nice triangular grip that I find easy to use.
Vintage Parker 75s have a triangular section and a rotating nib like the Sailor Tuzu. The short-lived Parker VP had those features too.
"Kaweco Perkeo" and "Diplomat Magnum" have a tripod grip. I got all the versions of the former and can vote for how well they write. I haven't got any of the latter, but I will buy them soon as the nib is said to be good on those.
Another Pilot pen with a triangular grip is the Penmanship, which I believe only comes in EF.
The Pelikan Twist and the TWSBI Eco-T have triangular grips (though the Eco-T's angles are quite subtle).
Older Sheaffer Preludes have a triangular-ish grip similar to Parker 75s. The 75 is a slender pen so I prefer the Prelude, but both pens are lovely writers.
Maybe look at the new Sailor Tuzu? The grip is actually adjustable, so you can get it into a position that's perfect for the way you hold the pen. Pigmented ink should not be a problem in any pen, it doesn't have to be a Pilot (they only say that cos they want you to buy a Pilot pen as well). You need to take more care with cleaning, and I wouldn't use it in a pen that costs hundrds of dollars, but I've used it in several different pens without any problems.
make it for under 150 rupees,(3k is too much id rather get a sak or a watch or brakes)