Give the Clays a fair chance and there is a very good probability it will shoot fine even with what you consider poor metering.
I use the RCBS measure with Promo (a very similar flake) and find that loads shoot good down to somewhere between 3.0 and 3.5 grs. Yes there are velocity variations (more from powder position than from charge variations), but they still shoot good.
Your Titegroup should also work well. For about a year when I was unable to re-supply my Promo (Obama powder run days), I found a jug of Titegroup and used it for a replacement. I was able to work up satisfactory replacements for all of my Promo loads and have stocked Titegroup ever since.
After I was able to get Promo again, I ended up sticking with Titegroup for anything I wanted to shoot that would use less than around 3.5 grs of Promo. You will use a little more powder with Titegroup, but the metering is just so much better (especially in very small charges).
I load between 600 and 1000 rounds a month for target shooting with my son. Most are 327, 38 SP, 357 Mag and 357 Max with Promo or Titegroup.
I ran Quickload for Clays and Titegroup to estimate charge needed for 900 fps. You did not specify barrel length so I ran a number of choices. Quickload uses muzzle to breech for length and I ran the numbers for 950 fps to account for an estimated 50 fps loss from the cylinder gap. This is for a 158 gr cast with a 0.420" bullet seating depth.
For 4.2" muzzle to breech, 950 fps is predicted from 4.6 gr Clays **
For 4.7" muzzle to breech, 950 fps is predicted from 4.4 gr Clays.
For 5.7" muzzle to breech, 950 fps is predicted from 4.1 gr Clays.
For 7.7" muzzle to breech, 950 fps is predicted from 3.8 gr Clays.
** Max listed charge from Hodgdon
For 3.7" muzzle to breech, 950 fps is predicted from 5.4 gr Titegroup. ***
For 4.2" muzzle to breech, 950 fps is predicted from 5.1 gr Titegroup. ***
For 4.7" muzzle to breech, 950 fps is predicted from 4.9 gr Titegroup.
For 5.7" muzzle to breech, 950 fps is predicted from 4.6 gr Titegroup.
For 7.7" muzzle to breech, 950 fps is predicted from 4.1 gr Titegroup.
*** Should be ok as Hodgdon allows up to 6.1 for a jacketed 158