Firstly, I hope you're rich... the Super Spiker (though the one in the photo looks a bit crude) will sell used for around $4,000.00 + cases.
The Stretching you picked out can be found in the Paul Osborne Illusion plan books... I'd suggest you invest into these and all other plan books you can get your hands on... the Rand Woodbury and Jim Stinemeyer books of course are very important as is Gary Darwin's book INEXPENSIVE ILLUSIONS.
I've explained this time and again with young people wanting to move into this realm. The first rule of thumb being to know that you can get the kind of work, the amount of work and the rates required for supporting an illusion act. Your stretcher requires two girls, I'd also suggest two guys to help you out (minimum) and at least one additional backstage "Show & Unit Manager"... that is, if you aren't dealing with animals at all and your other four staffers are as gung-ho as you are and willing to do some actual work.
In order to support even a basic Illusion act that is on the road, you need to see no less than $10,000.00 a day coming in... that will just barely cover payroll, transportation, housing, up-keep, insurance, agent fees, advertising, etc. For most of us that level of income ($50,000.00 to $70,000.00 a week average) must be generated on the weekends e.g. you have 3-4 days each week to make your nut.
Too, you need to add to your investment list the cost of decent lighting, sound, set pieces and of course a truck for moving it all around and possibly a van for moving the crew around.
Yes, I'm being hard on you but it wouldn't be kind to be any other way. Grand Illusions are fun and wonderful but most end up in the same shoes worn by the typical farmer -- property rich and financially broke... everything will be tied up in "the show" and though the staff gets paid, you aren't... you're the last person to get paid for that matter, when it comes to any kind of business venture.
Now, if you want follow this notion you need to look at what's going to be practical to the kind of venues you know you can get booked in. The Spiker can work in the round but it's big... that particular stretching is also a bit huge and don't pack well and does have some sight line issues (you also need to start it either back stage or behind a front curtain so you can set things into place). If you are looking at levitations then you must deal with angles, lighting, and insuring that your lift unit can be secured properly to prevent tip over (and it happens)... the list goes on and on from there. That is why most start-up acts have the same basic collection of big effects; a Broom or Sword Suspension, Zig Zag or Mismade Lady, Sub Trunk, Hindu Sword Basket or Temple of Benares, Lakes styled Head Chopper or a Spectator Sawing.
Very few will travel with a floating ball or dancing hank unless they have one of the more rare self-contained units or zombie styled control.
I'm more than willing to help you figure things out for yourself, but I think you need to take a step or two back and look at the business side of this element before getting in too deep with things.
