Wheel question

Building a Beta 300 oil burner for street/track day use. Struggling to find much on 17" wheel choices. Looking at 3.5" front and 4.25" rear. Not wanting to spend a huge amount so the $1900 Beta wheels are a non starter.

Questions:
Spokes or cast/forged? Pro and cons of each? Not thrilled with the idea of running tubes but lots of near bolt on choices for spokes. I like the looks of many of the OE takeoff wheels out there and have the ability to make my own spacers. Is there a particular OE takeoff that is well suited for putting on dirt bikes? Looking at RC390, R3, etc.
How do weights end up comparing?

Also, have laced up hundreds of bicycle wheels but never a motorcycle. Can go that route if it's the best way.

Thanks.