Adding American Sign Language (ASL) versions of information content to websites can improve information accessibility for many people who are Deaf or Hard of Hearing (DHH) who may have lower levels of English literacy. Generating animations from a script representation would enable this content to be easily updated, yet software is needed that can set detailed speed and timing parameters for such animations, which prior work has revealed to be critical for their understandability and acceptance among DHH users. Despite recent work on predicting these parameters using AI models trained on recordings of human signers, no prior work had examined whether DHH users actually prefer for these speed and timing properties to be similar to humans, or to be exaggerated, e.g. for additional clarity. We conducted two empirical studies to investigate preferences of ASL signers for speed and timing parameters of ASL animations, including: Sign duration, transition time, differential signing rate, pause length, and pausing frequency. Our first study (N=20) identified two preferred values from among five options for each parameter, one of which included a typical human value for this parameter, and a second study (N=20) identified the most preferred value. We found that while ASL signers preferred pause length and frequency to be similar to those of humans, they actually preferred animations to have faster signs, slower transitions, and less dynamic variation in differential signing speed, as compared to the timing of human signers. This study provides specific empirical guidance for creators of future ASL animation technologies, and more broadly, it demonstrates that it is not safe to assume that ASL signers will simply prefer for properties of ASL animations to be as similar as possible to human signers.