There is no maximum limit for both accounts, if you read the maybank isavvy thread, there is people with 1M using this method. But daily fast transaction max is $200K so if you have alot you need either do a couple of days or using cashier order. Minimum is $500. Every 2/4 months they have different promotion rates check the maybank isavvy page. Interest is in monthly.
Min 10k for Bonus Interest.
$500 is avoid fall below fee.
https://info.maybank2u.com.sg/promotion/deposits-banking/fresh-funds-top-up.aspx