Hi. It isn't a good idea to make changes to both at the same time as whatever your results you won't know which insulin is responsible.
Testing your basal first is a good idea. It is recommended to adjust it in 10% stages and wait a few days, not altering your bolus dose. So if you're taking 24 twice a day, change it to 22 or 21u and see how your body reacts. Keep a notebook and document your results. If you notice they are too high then increase one unit per dose every few days. If you notice you are then hypo'ing or going into low ranges then perhaps it is your bolus. In that case you will need to look at changing your ratios.
Keep your basal to 24u and look at having less bolus with each meal. If you do this gradually you will be able to work out the correct dose of basal you require per meal or per carbohydrate intake.
There is also the possibility it is the food you are eating. Slow acting carbohydrate, if eaten at the same time as a full bolus dose, will give you a hypo before your food has been able to break down into sugar. In that case you will hypo, treat the hypo with glucose, then consequently go high later when the sugar from the food has been released.
It is also worth mentioning that I have been T1 for 2 years and still experience dramatic fluctuations in bolus requirements from one day to the next. There is no real explanation for it, your body simply becomes more or less insulin resistant.
If you have any questions don't hesitate to ask.
