The 360/365 calculation should not matter unless the rate is the same for each (in which case 360 would be better)
For example, €10k deposited for 1 year at 2% on a 365 basis is calculated as follows:
10,000*2% = €200 (before DIRT). €200/365 = €0.547 per day
To get the equivalent 360 day rate, divide the interest rate (2%) by 365 and multiply out by 360 - so (2% / 365) * 360 = 1.97%
So one account on a 360 day interest basis at 1.97% will earn the same interest as 2% on a 365 day basis.
10,000*1.97% = €197 (before DIRT). €197/360 = €0.547 per day