Almost set up

It's been a long time coming. My TT is almost ready to go. Here's what I've got,
Basis 1400 w/clamp, Rega 900 with rewire (Origin?)
Ortofon Bronze running into a Rouge 99 Magnum.
I'm awaiting tubes then I'm ready to go.

Where should I start with VTA? Someone said the arm
should be horizontal with the platter. The arm is tapered.
Should I align the bottom or a visualize a centerline?

Thank you.
Hi Fredg,
The starting place for vta is the diamond itself should be a 90 degree angle to the album surface or the diamond sits perfectly straight up and down in the album groove. You are trying to replicate the original cutting stylus angle, which also requires, most phono cartridges to be slightly twisted in the head so that the stylus tip rides in the groove correctly. This would be a hard explanation on a forum like this, I'll look around and see if I can find a link for you.
Alright, looked it up, final tracking angle is based on the sylus cantiliever, so the little tube that the diamond is mounted on should be 18 to 24 degrees. I recommend to shoot for 20 to 22. Get a protractor and check out 20 degrees, replicate that and you will be right in the league and a great starting point. Let me know how close your diamond tip is to the 90 degrees that I originally recommended.
Hi, Fred: having the tone arm horizontal with the surface of a typical 140-150g LP is a good starting point. The tracking force (VTF) should be set in the middle of the recommended range and yes, use the centerline of the tone arm tube for sighting. If the stylus was correctly attached to the cantilever by the manufacturer, you'll be close to the desired stylus rake angle.

If you do a search here at Audiogon for "SRA" you'll find all kinds of information, and lengthy debates about how to set it. The reason for paying attention to SRA is that when the record is made, the cutting head is drawn through the vinyl at a forward angle so the waste material from cutting the vinyl is pushed up out of the groove. By setting correct SRA to replicate the cutting head angle, the sides of the stylus will correctly contact the walls of the groove and you'll get better sound. Vertical tracking angle (VTA) has been the common term used for cartridge alignment but SRA seems to be gaining acceptance as the more accurate and useful parameter. Again, a search will provide plenty of reading material.

But, it can get complicated in a hurry. Records are different thicknesses so if you set SRA for one range of record thicknesses it won't the the optimal SRA for thicker or thinner records. Some people change tone arm height to adjust SRA for each LP. Plus, the SRA is affected by VTF. Decrease VTF and the tone arm rises as the cantilever suspension relaxes and SRA increases. Conversely, increase VTF and the tone arm lowers as the cantilever suspension compresses and SRA decreases. But, the change in SRA with increasing or decreasing VTF is compounded because changing VTF also changes how the cantilever aligns with the cartridge body and how the cantilever generates the signal within the cartridge.

"Sheesh, I just wanted to play some records!"

Keep it simple for now. By setting the tone arm at horizontal using the mid-range of recommended VTF on a mid-range thickness LP you'll be close for most LPs. The SRA won't be ideal for thicker or thinner vinyl but it won't be that far off. You can experiment by raising the tone arm to increase SRA or lowering the tone arm to decrease SRA to see if you find the "sweet spot" for your cartridge and stylus.

Or just play some records. '-)

Have fun!