Bert H. said
I use IMR 4198 for a fair number of the older Winchester cartridges, e.g. 25-20 S.S., 32-40, 38-55, 40-70 Ballard, 40-70 Sharps Str., 40-90 Sharps Str., and 50-95 WCF.  When I decide to start reloading 33 WCF again, I will give it a try and work up a load.
I also very recently began reloading my 222 Remington Magnum with it (24.2 grains under a 40 gr. V-Max bullet).  It is the only "modern" cartridge I reload using 4198.  I recently bought 2 lbs of the H4198 that I intend to use for the 222 Rem Mag.
Bert
  

I went through my loading manuals and researched over 40 Winchester calibers for our early guns.  I found loading data using 4198 for at least 30 of these calibers.  I did not find 4198 info on the 44, 38, 32-20, the 2 Military loads for the Hotchkiss, 40-72, 7.62 Russian, 303 Brit, 30-03, 30-40, 22 WCF, 405 and 35.

Again, these are just my manuals.   In addition to 4198 you should have some 2400, 3031, 4064, 4227, 4895 and maybe 4759. 

I also very recently began reloading my 222 Remington Magnum with it (24.2 grains under a 40 gr. V-Max bullet).  It is the only "modern" cartridge I reload using 4198.  I recently bought 2 lbs of the H4198 that I intend to use for the 222 Rem Mag.

Bert

I did a study and found that the majority of the old Winchester large calibers can use 4198. 

Bert H. said
Bill,
Why not load your 45-90 with 4198?  I would start with 36 grains and work it up slowly to find your accuracy load.
Bert
  

  I like Bert's idea. I use 4198 in 45-75 and 50-95 in 1876s and 50-110 in 1886s, it's very manageable and consistent, great powder in big cases. T/R  

Why not load your 45-90 with 4198?  I would start with 36 grains and work it up slowly to find your accuracy load.

Bert

Zebulon said
The next time I see a good copy of Pet Loads at HPB, it's coming home with me. I had one in my hands a couple of years ago but passed on it because I'd found a Franklin leather volume I had really wanted for a long time, Penn Warren's All the King's Men.  Haven't seen a decent Pet Loads since. 
From Waters' obituary, he really was a man for all seasons. 
  

Zeb-

My copy is a bit more recent but this particular article was written over 40 years ago. As usual his loading tables are very concise but the article puts those results in context. Waters agrees with TR on his preference for the IMR3031 powder but H4895 powder was quite acceptable in Waters' testing.

Mike

From Waters' obituary, he really was a man for all seasons. 

Mike

TR said
  I've always used 3031 in 45-90 1886's. I'm sure there are other powders that will work but I would not use 4895. I use it in modern guns like 270, 06, and  300HH. It is a lot of bang for an old black powder gun. T/R
  

Hodgdon specifically states that H4895 is ideal for "reduced" power loads.  They state the "60% rule".

Microsoft Word - Hodgdon H4895 reduced rifle load.docx (hodgdonpowderco.com)

For something like the 45-90, I would not be afraid to give it a whirl.

Bert

It doesn't have a section on 45-90 but does have one on 45-70. I've attached a copy. 

Note that the loads are for Dupont, not Hodgdon. In a minute I'll check Lyman's Cast Bullet volume and two of Venturino's books. If I find anything more, I'll send it.