Here's the URL of the most current and comprehensive 'rig tuning manual' on the internet. Although written by Seldén, a mast manufacturer, the info provided applies to 99% of all other manufacturers & types of rigs etc. - fractional, masthead, B&R, etc.
And to keep your expenses down to a bare minimum, you dont need a tension gage, if you follow and understand 'manual rig tuning using just a 'meter stick', etc. .... all in that URL listed manual. .... the "folding rule method" on p. 28
http://www.riggingandsails.com/pdf/selden-tuning.pdf