Ok
For better absorption take M3 20mins before food and additional 2hr testing after to see what foods you can tolerate and its lack off spike to increase/decrease units.
Humulin I is just a basal insulin only so stick to taking it same time everyday, if you can.
So your team has given you a basal and a basal & bolus injects to take one each per day?
So basal (humuin I) on a morning irrespective of food so no 20mins needed. A M3 mixed insulin (should be 20mins before evening meal) to deal with difficult evening meal high bgs.
You could change your evening meal to a low carb one to take less M3 but don't take none til you have perfect hba1c result.
Take these both meds to see what your settled bgs are. At least 3 months then revise.
Remember to test regularly to avoid hypos. Treat hypos effectively but try not to over treat them otherwise swinging high/low bgs for hours.
If you do do low carb evening meal and reduce and reduce M3 to nothing ask to see your dn sooner to update them.
Don't confuse these injections with metformin, which is needed longterm to help with insulin resistance.
Your influence from your slow insulin's will not be fully appreciated for 3days so continued use is needed to see how they are helping. Half influence will only give half the picture.
M3 has no fast acting insulin just medium acting and slow acting.
Had you had any through the night hypos yet?