Although you can, if you want, submit chapter groups of a novel through the queue in the "usual" Critters fashion, novelists should consider also doing a "Request for Dedicated Readers." An RDR is like an ordinary entry in the queue (it's often added to a chapter group), but when that entry comes up for reading, it becomes a request for Critters to devote themselves to reading your entire novel. Your RDR generally consists of a description of the novel and any special constraints unique to you (e.g., a publisher's deadline).
Readers communicate directly with you to receive chapters and send critiques. Readers receive generous credit based on the number of words they critique, however, they don't receive this credit until they have completed the novel (or whatever part of it you want done -- in other words, you control when they're finished (within reason, I mean, you can't expect them to read chapters more than once, for example, though you could negotiate this with them)). It's very flexible in that you only accept the readers you want (checking up on them in any way you see fit), and only the readers who are interested in your work will apply. You are in charge of the time schedule (though you need to spell this out in advance).
You can send chapters through the queue like usual (though readers can't get double credit), or, if you prefer, keep the chapters private between you and the readers only. You design the program with your readers.
Does it work? Well, our first test case was a sort of worst-case trial-by-fire: A pro author (David Niall Wilson) with a short deadline. He reported that it worked out "admirably," and we have since had numerous happy customers.
The general process to do an RFDR is to submit either the first few chapters to the queue plus marking the "rfdr" box on the submission form, or just submit a synopsis and whatever verbiage you think will entice reviewers to grab it. (In the first case, of sending part of the book, people will be able to get credit for critiquing just that portion. You can keep sending chapters through if you like. I suggest a max of 5,000 words per chunk.)
The full "rules" are here.
The author should go here to award credit when readers are done reading.