Out of the 150K, how much of that represents graphics and/or code or pure indexable body text? With Google, there are pages that rank purely on the basis of PR and inbound anchor text - that's not the case with Inktomi.
How much text there is can have a bearing on keyword density, for one thing. For Inktomi it's just good old-fashioned overall page optimization, paying attention to all the little details.
Regardless of whether a given search engine *can* handle pages over a certain overall file size, we always hear that one search engine or another has a preference in ranking for either small or large pages - pages heavy in text or with little text. Some people say to have a minimum of 250 words of indexable text on a page, others say more. Some like less, especially for Inktomi. How big a file size would a 250-word page have if it's not heavy on graphics?
We all have a different experience, but from what I've seen for Ink small, snappy pages do well that are a bit higher in density than we'd normally do for Google. There are a few factors that give an edge with Ink, but basically it's plain vanilla SEO - and attention to usability and quality of user experience never hurt, no matter what.
Conventional wisdom for SEO is that page file sizes be kept smallish. We're even advised to put scripts and styles external to keep size down. Opinions vary, but for Ink about 20K total is fine, personal preference is as far under as possible, as far under 10K as possible even better.
Others may have good results with big pages, but I can't recall anyone having shared that they'd had consistently good results with big file sized pages.
If we PAY for pages to be listed I think we need to go with what we feel reasonably comfortable with as having a chance, though having that frequent spidering for a test case could tell a lot. I wouldn't personally do more than one big page just to see what happens.