Collecting under Reg B for HELOCs shouldn't be that big of a deal. GMI is only required for HELOCs under Reg B if it is "an application for credit primarily for the purchase or refinancing of a dwelling occupied or to be occupied by the applicant as a principal residence, where the extension of credit will be secured by the dwelling". As HELOCs are often equity loans (and not for a purchase or refinance), then GMI is not required.
That said, you will have the rare loan that is for a purchase (or refinance) where you need to collect it (though you technically don't need to collect it under B for a refi where you already have it on file from an initial purchase).
The link TMatt87 provided is the citation for all of this.
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Adam Witmer, CRCM
All statements are my opinion, not those of my employer, and should not be taken as legal advice.
www.compliancecohort.com