Proper way of setting up my PR Blog Network Please give suggestions

I know this is all over the forum but please give your suggestions here to see if I am going about it correctly and would like to ask few questions.

I bought several pr sites mostly in restaurant niche one travel/web design and just bought a pr6 site but its no niche like just 5 letter .com that means nothing no niche. Most are low to medium authority numbers like low to med value.

Some have dropped in pr one went up.

I wanted to start using for my sites and offer link service.

I just let sit for a while after I bought few weeks even yea I know should of added quick content. So I finally added one article with related image fairly unique but short just one for each site. Deleted all links going out like bottom theme link any wordpress links stuff like that.

I did a quick test for a friends site I have looked at for a year it is a restaurant KW is low comp about 1300 local city restaurant search term not bad. It has always been nowhere to be found not in top 100 at all never.
So added one contextual link to short sales promo mention as post with one logo image with same KW as image name on one pr2 and one on pr4 on my restaurant sites and quickly jumped to #22 then about a week later settled on #17 now its on #16 that was about 2 months ago.

Remember most of my sites have low value from was PR2 to PR4 now PR0 to PR4 and one new unused PR6.

So my questions and please give suggestions:

How do I maintain and if possible get back PR for my sites?

* Do I add new unique content every week, month or just say add once for each linkback and not touch at all?

I wish to go the rout of say only use 1 contextual linkback per client per content. No sidebar or other type of blogroll links for better stronger link juice.

20 OBL per site so will have 20 posts on main blog posting area with one contextual linkback and add one image like logo or image.

* Picking themes will any basic one do I see some have place were we can edit code some do not would like to know easy way of deleting link of say author and comment and all others I know there is a plugin for date but hope there was one for all of them to stop any and all link juice from escaping.

* About hosting makes sense even if the price is great not to use any hosting that lets everyone and yes google that they are there to do seo hosting letting you know the purpose is to cheat google.

I have seen here and other places offers for 60 ip's for $30/mth thats .50 per ip forget the thread. So are IP offers the same as shared hosting and normal hosting offers like at gatorhost and host9 and others?

* For PR sites like my generic new site I bough that has no niche at all just random letters does it matter if I add different niche clients or if I add the first client is a dentist will I have to add all others only dentist or dentist niche?

Or will I be able to add dentist, restaurants, furniture stores whatever as long as that clients content is related to their niche linkback?

Sorry for way long post.