You can only manage what you can measure, so step one is to get EVERYONE registered.

Basically last year and in the coming year this market will see hundreds of brand new medium to large houses specifically aimed at STR and they are NICE! 

If I am aiming for the national tenant, what kind of TI per sqft shall I expect, how much security deposit I shall collect and  how many month of rent I shall ask tenant to pay advance to execute the lease (1st and last month of rent or more)?

Multi-unit properties can be a great investment, and it's exciting that you're aiming to own a couple by the time you're 30. 

I still do not see the combined ratio as a legitimate measure of this. 

All cash invested $1m Market value: $1.2m= 83% cost to value (17% profit)What are people usually aiming for at a minimum? 

Most units are inspected and turned in less than seven days from move-out.Within 24 hours of work completion, PM inspects to verify and updates photos to document the condition of the rental before a new tenant occupies.I aim to turn all units within seven days of the tenant vacating.

We aim to have a spread of at least 10% ARV so if we know we can sell in a specific area at 75% ARV - repairs, our MAO would be 65% ARV - repairs. 

I am aiming to buy my next property closer to home and was interested in looking in Bristol.

All in all, you'll likely get a discount on the property because of the zip code but be prepared for high needy calls and installing some extra safety measures to protect yourself and your guest.