Company Pension Plan is closing offering Pension transfer of entire amount or part to 401k OR (withdraw all or part) as lump sum pay out. When age over 59 1/2 How do we determine max partial withdrawal keep AGI levels below Married filing jointly

For 2021,  Employer is offering one time opportunity to either transfer all or part of Pension Plan to 401k, or take all or part as a lump sum payment.  Age is over 59 1/2. We want to take a partial lump sum.  How do we determine maximum partial payment we could take from the retirement, such that it will not increase our Maximum Adjusted Income level over current bracket at 25,000 taxable income (line 15).

We are married filing jointly, if our 2020 taxable income was 25,000 (line 15) what is the maximum pension we could withdraw that will include automatically 20% (no penalty) withheld in that payment, that would not increase our taxes owed above the 20% withdrawn?  

What max amount could we take from retirement as lump sum if we want to get a partial refund of the 20% taxes automatically withheld based on current AGI above of 25,000?
What max amount could we take from retirement as lump sum if we don't expect any refund of 20% taxes withheld and use all money withheld to pay 2021 taxes and owe no more?

PS:  I will be using Turbo Tax Deluxe in 2021 as I have every year for the past 7+ years.