I make just a few PCBs and I have used the electroless tinning solutions but once made up they don't last long so by the time I next need it, it doesn't work any more. I came across a simple method for electroplating tin on a PCB. The board would have to be plated before etching so all the copper is connected together. This is no problem as I make my PCBs with a CNC router.

The electrolyte is made simply by dissolving tin in hydrochloric acid (SnCl2). You use a tin anode and the PCB copper is the cathode. The description says that hydrogen is released from the cathode but I don't understand why that is. I would have expected the process to simply transfer tin from anode to cathode.
http://transistor-man.com/electroplating_busbar.html

Q1. Why is hydrogen released?

I also looked at a process for plating the holes in a board. That used electroplated copper.

Q2. Do you think that would work as well with electroplated tin in the holes?

 

Have no idea how to get all patches connected with ground pole. But if before etching - have no an idea how to etch then. Thus the electrolytic is very bad idea. Instead may try to use the classical hot bath in 100C water floating dish with Wood metal or Roze metal covered by glycerol. Any additive like NH3OH or aspirin acid (acetyl-salicyl) are welcome in small quantities. Other receipt is braiding plunged in Wood metal with colophonia in spiritus vinae concentratum, the same way at the hot water. Or most simple - with normal tin with normal colophonia in spiritus and very wide-tip soldering hammer. Mild metal brush then is handy tool for some not so nice zone repairing. However, please believe me on word, in case of high frequency Your result will happen far too higher, if instead of tinning apply the photoresist lacquering. Those lack tins are not so expensive at ebay, but are giving extraordinary professional outlook as well the RF (skin-effect depth) as well Your layer may give.

 

Via through=hole metallization is a nice thing, but it is so complicated, that only large conveyour based shops may permit such. Or order Your pcb in such and forget all problems around processing in kitchen (but price), or forget the metallization. Its not so complicated to solder the 1000 short wires in via`s places.

 

Have no idea how to get all patches connected with ground pole. But if before etching - have no an idea how to etch then.

Take bare copper laminate. Drill holes. 'activate' holes - i.e. coat inside hole with conducting stuff. Tin plate whole board and inside holes. Use my CNC router to 'etch' the tracks. Now you have a tin plated pcb with plated through holes.