Need help figuring out max lifts: Greyskull related

So, I’ve been on the same regimen for nearly six months and down to about 15-18% bf depending on my diet. I Wanted to change it up as I feel like I’ve plateaued.

I think I’m maxed out on this workout and wanted to attempt the GS methods come mid- Nov (right around the holidays.) I’ve not maxed any lifts the last six months; but have continually added weight over time. Currently on a push/ pull/ legs split where I’m hitting each group 2x a week.

My question is can anyone help figure what my max range is on the following lifts? Not what it will be but what I should be around?

(Exercise/ weight/ reps)

Bench: 135 (12) 185 (8) 185 (8) 205 (6) 225 (5)

Squat: 135 (12) 225 (8) 225 (8) 250 (6) 275 (5)

DL: 135 (12) 185 (8) 205 (8) 225 (8) 245 (6) 265 (5) (but feels like I can do way more after 5 like maybe another 3-4 reps)

I have read the thread on GS and probably need to reread it a few more times; but I need to know what these max reps should be around before I begin GS. That’s why I’m taking the next few weeks to figure it out.

Any suggestions would be great. Thanks.

Also, what other leg and back exercises are you guys on GS doing on these days? Hack, Leg Press, row machine, etc?

I appreciate it.