I will be exploring Bangkok in 33 days this March and April.
I assume you will have your tourist visa all sorted? Visa exemption (if your passport/nationality qualifies) allows only 30 days - unless you are going to do a visa run/exit Thailand before your 30 days are over.
Is this bangkok sightseeing tours enough?
I can't tell you if it is enough or not but it seems to cover the 5-6 main tourist spots. Given you will have 33 days you will find a while lot more to explore in BKK. If you provide more info about your interests and dis/likes I'm sure others can point you to more things to see and do.