In answer to your questions:
1) Appendix E (the seismic appendix) was rewritten for Addendum 4 of the 10th Edition. If you want the procedure before this 4th Addendum, no TANK does not have a provision for this earlier method.
2) Yes, TANK can design a "rafter only" cone roof - no columns or girders.
3) No, TANK only sizes the anchor bolts, the software does not design anchor chairs at this time.
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Regards,
Richard Ay - Consultant