So far everything I have encountered is based on strategies that involve using debt, for all the mathematical reasons that I do understand. 

Mathematically speaking you're right and I've calculated the same too.

The weight reflects how important that decision factor is to you and you select the lead generation method that exhibits the highest score.Forinstance:DMM: Low ROI, High Stress To Deal, High Effort To Deal, Immediate Results Per Effort, etc. etc. and you add all the scores of each decision factor.You do that for SEODMMCold CallingDriving For DollarsAuctionsBandit SignsAnd you find the best lead gen for you that fits your personal phsychy.Although this is a very valid and scientific mathematical way to make it work (numebrs never lie) I do not agree with this.My character is as follows...

Tax rates, mathematically, HAVE TO GO UP to meet the obligations made presently/in the past.

This point of view is of course from purely an mathematical investment standpoint there are however other indirect factors that are hard to put on paper as well, the walls may help you rent the units faster (less vacancy = + cashflow), they may help you show the units better (better quality Tenant = less headaches, less turnover  = more cashflow), they may also add to your ongoing costs since panels do last longer whereas drywall tends to get 'holes' punched in it every now and then.

In the world of mathematics, there is a thing called  Sets and subsets. 

I think estimating  these rehabs, which is essential to the mathematics of determining a proper price to offer your distressed seller and a big reason wholesalers get a bad rep, for a reasonable cost could make or break the beginning wholesaler.

as someone who has the same idea as you  Pay off my personal residence ( a life long goal) and I am just about there.I could care less what anyone anywhere told me what was mathematically better..that all said you don't have to go far from Cameron park to find deals that will cash flow.. so you may want to stick close to home if you have not owned rentals..

If it does then move forward , if it does not then it may be a good deal but not a good deal based on your end goal.Remember real estate very simply is math, it is a mathematical equation to get you a result.

You can disagree with the belief all you want but it's a mathematical fact.