We too often resort to factually emaciated RFPs, doling out facts on an as needed basis, restricting the questions that can be asked, and limiting due diligence. Telling the firms who are proposing too much takes time, runs risks, and leads to little gain, supporters of limited information would argue. The law firms that bid feel starved for enough data.
A different approach is to sit with key partners of a trusted and familiar law firm, share with them completely your ledgers and matter management information, and hammer out an arrangement based on both sides equally analyzing and understanding the available data.
Moreover, an RFP process can consume huge blocks of time; to circumvent it by negotiations with a known service provider can be very efficient, although it mutes the market discipline of competition. Still, to be able to offer the portfolio of work to other firms always hangs in the background should the negotiations fall through.