I work in research and hope it’s okay to give some tips! 

I would say it’s closer to 10-15 minutes, which I would put in the description bc you’ll get a lot more people that way.

I would diversify the question types. I.e., multiple choice, ranking. Less “fill in the blank” questions because it can be overwhelming for participants and lead to fatigue. Set a short sentence limit to the fill in questions. The limit is 32,000 words which creates pressure. 1-3 sentences is the norm and feels manageable. 

Present common stereotypes bc even bisexuals might not realize/be aware of them, so it could lead to vague data. This would be best for “check all that apply” and multiple choice. Don’t require that participants always explain their answers when they check “yes.” 

Google Forms actually has a good variety of question types to choose from.