Working with multiple lenders after an LOI

I am currently under an LOI and I am in the initial stages of working with multiple lenders, mostly SBA. The reason I am currently working withe different lenders is because I am seeing that each of the lenders have different criteria even for the same deal, based on industry, down payment, DSCR etc.

I would like to be on the safe side than sorry to ensure I am able to secure the loan in an acceptable terms.

At what stage should I narrow down to one lender. Is it only when the loan gets approved? Just want to understand the general principles and guidelines here and what others have followed in general.