You can use as much of the 4895 and 748 as you want w/o to high of pressure for you rifle. 

I delevoped and shot a load for CBA back in the 90's, using AA2520 (about the same burn rate), I used almost a case full (32 gr) and BSed a 220 gr bullet in front of it, getting 2157 fps average so, I think your safe with the 170 gr bullet with any powder charge that you can seat the bullet with. My rifle was a Clerke HW.

Start where ever you like and work up. I'd start no lower than 20 gr to get them to burn. It gives you a lot a loads to try.

Frank

On-line resources might help. Google-search 32-40 load data. Most of the major bullet and powder companies have load data web sited.

This site lists loads for 5477 and 4895 with 170 gr Hornady flat nose bullets  (assuming they were for tube mag leverguns)

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Looked up jacketed 32/40 loads

Whelen in “The American Rifle” 1918 list 3 Factory  loads for the 32/40   1427  FPS lead bullet with black powder.  1752 FPS Jacketed bullet load, and another 2065 FPS Jacketed bullet load with the note “smokeless steel barrels only”   He has loading data but none with powders in production today. 

Sharpe’s “Complete Guide to Hand Loading” later book 1937,  Has lot of loads few with modern powders.  He does list a 1870 FPS load with 165 gr Jacketed bullet using 4198 21.5 grs.

Today with powder availability like it is I would use a common 30/30 powder take minimum 30/30 loads as a starting point and work up to 1750 fps. Your Rifle modern design and modern steels would probably do ok with the 2000 foot load, limit being the brass not the gun.

My Lever Silhouette set up Marlin 36A 30/30  am using 4227 with light varmint jacketed bullets  Varget with 170 Jacketed bullets.  Would use 3013 or 4198  as well.  4227/Varget I have on hand in quantity. Others unavailable

Boats

Found my load data for the 32-40W Stevens 44 1/2 I used for deer hunting one year in PA, it had a 26" barrel. 
I loaded 23grs of Reloder #7, using the Hornady 170fp bullet, overall loaded length of 2.550", chronographed 1960fps at 15ft, just under 1 1/2" groups open sights at 75yds, a very nice low recoil, clean burning load, note says I tried 25grs of accurate 2015, it did not burn as clean or group near as well. 

Good luck Ray_Newman with your rifle, Mike

T/C made a 32-40 barrel for the TCR.  I have a couple of pages of data somewhere that was developed in the TCR and there are some snappy loads listed.  I think I found those loads at loaddata.com IIRC.  In my 44-1/2 I use 30 grains H4895 with Lyman 321297 for deer.