Well, if the tank isn't even on the bike, I don't think hydrolock will be a problem.
Hydrolock happens when one of the floats gets stuck open, generally because debris gets between the float needle and the seat. You could always put an inline fuel filter between the tank and the carb to help catch any debris, and install fresh fuel hose as appropriate. Some fuel filters are better suited for this; do a forum search to see which ones are on the 'should work fine' list. Other filters can cause fuel starvation, and as the Connie is a gravity feed system choosing the proper filter (with proper angles on the ends so you won't end up kinking the fuel line or whatever) is essential.
Hydrolock is not a common occurence, so as long as your fuel system is clean you should be OK. Definitely keep the overflow tubes on your to do list, or get the manual petcock if that's the route you'd rather go. You don't really need both.
I trust that you are doing the POR or whatever lining treatment to the inside of the tank tank, seeing you are doing all of that other work. If not, it is something that might be a good idea to do at some point. Older Connie tanks generally will eventually rust through, so if you have an older tank, it is a thought. But most older bikes have this issue, so it isn't a Connie specific issue.
