It’s not advisable to be so high, I try to keep in the 150 range till abt 2 hrs before the end and then I do a correction(if needed). With Lantus I took abt 2/3 of my regular dose and this usually worked out fine.
For the ‘breaking meal’ I increase my basal (stil b4 motzai) and overbolus for everything. If possible I sometimes already bolus a few units 1/2 hr b4 the end to give the insulin a chance to work b4 loading up with carbs. Eating low carb is a great solution, that’s if you can resist the cakes;)