For peak sales I'd say Q1 2019 (for actual post Kickstarter campaign online sales via stores) as this will coincide with possible next gen Nvidia GPU release - or mean customer only has to wait until same time period or Q2 2019 for AMD to launch their next gen card also, forcing Nvidia to release beforehand with a card potentially 20+% faster than 1080Ti which is VERY important to showcase the capability of the headset Vs competition.
Basically the later the better, for us, if Pimax are going for 90hz goal promise + the missing 'brainwarp' as if you wait another 6 months the technology should just be in place at the Pimax development department giving them a tiny 2 months window (Nov/Dec 2018) to ship out the 'backers' headsets first to us!!!
Also I think just over 1 year since end of Kickstarter campaign is a 'marketable' and 'fair' time to wait which should seem acceptable to most rational 'Futurists' and online reviewers salivating at the opportunity to critique the headset the moment it's launched.
Pimax MUST get this right, or they wil miss a huge opportunity to be a market leader, potentially superceeding HTC VIVE overnight = maximised sales and profit.
So deliver 90hz, brainwarp, superior FOV and we'll all be happy and the competition sad.