light load for 45 ACP 160gr w/Tightgroup

Need some help......I am now shooting 160gr Brazos 45 ACP using 3.5gr of BE powder. Nice light load for me and working well in my 1911 setup.  Running out of Bullseye, but have some Tightgroup.
Anybody out there using Tightgroup with this type of light load?  Like to know where to start.

I am using a 165 SWC over 4.4 grains of Tightgroup. Light recoil and tight groups for 25 yards.

I use 4.2 grains of titegroup with the brazos 160 grain head, with great results at the 25 yard line.

Thanks....I'll start with 4.2 and work my way up (if needed).

Never could get 3.5 BE to cycle with 160’s

4.4 N310 works really well for me