This is a very good question and I'm struggling with the same situation. You're looking to gain lean mass without putting on any (or at least very little) fat. You have protein high at approx 300gms. Now the question is where do you insert the additional calories (fats or carbs)? Also, what role should cardio play in the lean bulk.
You'll likely get many conflicting answers to the question. Here's what I'm doing:
I also have protein high at 340 gms. Many guys will say this is too much, but from experience it is about right for me.
I've been experimenting with the following macros: 35%, 45%, 20% vs 25%, 45%, 30% (carb, pro, fat) -- keeping the same total calories. I also reduce carbs by 75gms on non-training days. I training 5 days per week so only 2 low carb days.
Last week or so has been the higher fat menu. I'm not liking the results so I'm switching back to lower fat and higher carb diet.
I've been gradually raising calories from 2,600 to now 3,300 kcal. I've also gradually reduced cardio from 30 min/day 5 days/week to 15 min/day 5 days/week. I think the sweet spot for me was 20min so I'm going back to that.
Over the last 8 weeks I've gained 5lbs of lean mass and 1lb of fat. I think I've almost have my lean bulk figured out, but it definitely took some trial and error.
I guess my overall suggestion to you would be: 300gm protein, 55gm fat and then adjust carbs as needed. Take some away on non-training days and add more gradually on training days until you're gaining about 0.5lbs/week. Keep cardio as is for now.