Shinko 241 18x3.0 up front and 18x3.5 in the rear.

Here are three more Enduro tires that I have found and put on three of my 125's.
On a DT125B, I have these Duro Trial 54-P DOT 4PR tires:

I have these in front: 3.25X19 and 3.5X18, which I think are the original sizes for that year.

On an AT-1E, I have another style by Duro, the Duro 52-P 4PR, which are a Dunlop K-70 knock off:

Just have a shot of the front, but the rear is identical. These are not marked DOT, but I can't imagine an officer would stop you for anything but going too slow on an AT-1E. These come in the original sizes: front, 3.00X18, and rear, 3.25X18

On another AT-1E, I have this Mitas H-03 in 3.25X18 on the front:

with a NOS Cheng Shin trials style 3.50X18 on the rear. This looks like a good 50/50 tire, but I have not gotten the bike running yet to check out its performance.

I'm glad to read this. I have a bias towards anything from Nagoya (IRC tires are from there), so I picked those out of habit for my 175 since the Yokohama Trail tires on it might be original. They are hard, and cracking in spots. I saved them for fun, but they were not smooth to ride.

I found GP-1s that fit the front and rear.

Rear GP-1 Dual Sport 3.50-18 Tire - 302051
Rear GP-1 Dual Sport 2.75-19 Tire - 301533 (This one is in the front).

My cousin that does a ton of riding on various bikes/atvs told me that the 2.75-19 would be fine in front even though it is supposed to be a 3.00-19 in front, so I went with it. It seems to be OK so far, so I hope he wasn't BSing me and the tire is going to pop or fall off and make me eat pavement. Riding it around 40MPH and hitting bumps and such went OK!

There was an noticeable difference with cornering, and with zipping thru the grassy field area I sometimes cut through. I slid a bit in some swampy portions, but was able to not completely fall over like the Yokohamas had me doing.

I almost put these Wild Flare things on the bike with fire-pattern treads. They are neat looking, but not made for offroading, so I passed!

Put these on my CT1-B
Front Kenda 3.50-18 56P
Rear Kenda 4.00-18 64P
Obviously fatter than the standard 3.25 front and 3.50 rear but I couldn't get hold of a 3.25 18 for the front.
Rear is pretty close to the chain-guard but clears.
I'm happy with them and like the chunky look.

I like the look of the 3.5 in the front since you went with the 4.0 in the back. I was able to find 3.25 X19 front and 4.0 X 18 rear under Heidenau brand. I think that is spelling. They went on my RT1.

I have the 3.25 x 19 front and 4.00 x 18 Heidenhau on my RT1, they are great.
The CT1-B has an 18 front and they don't seem to make a 3.25 x 18 in that tread pattern.
The Heidenhau 4.00 x 18 is 7mm wider than the Kenda 4.00 x 18, which would have been very tight with the chain guard.

The Kendas look like a good, authentic tread pattern. I'll remember those for future builds. I love my IRC Trials on my DT400 but not sure what sizes are available. Nice, authentic tread pattern compared to the original Dunlops.

All of my bikes get dirt only tyres. The 78 is currently on a spicey chinese special 23 hours of riding and still in good shape was $57nzd delivered I could throw it away now and it would of cost me $5.70 per ride lol

Is there a consensus with regard to which modern tire closest resembles OEM on Yamaha Enduros, specifically DT250s? Shinko 241 looks close; anything better?

Heidenau K67 is my vote... possibly the only option if you have a 19" front wheel... they work well too.