Powerbook G3 Lombard hard drive compatibility

[livingfortoday]

So, I should be getting my "new" Lombard in the next few days, and one of the first things I'm looking to do is up the hard drive size from the 4GB that's in there now. According to lowendmac.com I have to use an ATA-5 drive, and it cannot take ATA-6 drives -

According to the Road Warrior and Other World Computing, the drive controller in G3 PowerBooks is incompatible with ATA-6 hard drives. When replacing the internal hard drive, you should be sure to obtain an ATA-5 compliant drive, which supports transfer speeds of up to 100 MB/sec.

Can anyone with experience with these machines explain if this is 100% true, or if there are exceptions, or what? ATA-5 drives aren't *that* easy to find, and though I'm only looking for 20 - 40GB, they seem kinda pricey.