That looks very much like the Lee 452-200RF, let's see what we have...
It's interesting, I originally had the Lee 200grn SWC selected, as soon as I switched to the RF bullet, pressures dropped markedly, so I'll say that your 7.1grn TiteGroup load should be fine, sticking to the published COL. At a higher velocity, your barrel will tell you in pretty short order if it likes that bullet/velocity combo.
Hodgdon data doesn't include HS6 with the cast bullet... very likely because of the potential velocities. Your stated that your bullets are poly coated, so that will help. Comparing Hodgdon's 200grn XTP data with the QuickLoad model, I would start with the starting HS-6 XTP charge of 11.7grn, that would very likely work pretty well... or it will show you need a heavier bullet for higher velocity. There should be other data to crossreference the 200grn cast bullet with HS-6, but I'm not at the bench at the moment.
Were I you, I would likely try the 7.1grn TiteGroup load... because you have that on hand... and see how it does. I'd be curious to see what kind of accuracy you would get out of that combo in the rifle barrel.
